www.fgks.org   »   [go: up one dir, main page]
Jump to content

Raph Levien: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous edit
Content deleted Content added
VisualWikitext
→‎External links: adding foss typography navbox
Add short description
 
(11 intermediate revisions by 10 users not shown)
Line 1: Line 1:
{{Short description|American software developer}}
{{Infobox person
{{Infobox person
| honorific_prefix =
| honorific_prefix =
Line 12: Line 13:
| pronunciation =
| pronunciation =
| birth_name = <!-- only use if different from name -->
| birth_name = <!-- only use if different from name -->
| birth_date = {{Birth year and age|1961}}
| birth_date = {{Birth year and age|1970}}
| birth_place = [[Enkhuizen]], [[Netherlands]]
| birth_place = [[Enkhuizen]], [[Netherlands]]
| baptised = <!-- will not display if birth_date is entered -->
| baptised = <!-- will not display if birth_date is entered -->
Line 27: Line 28:
| known_for = [[Advogato]]
| known_for = [[Advogato]]
| notable_works = <!-- produces label "Notable work"; may be overridden by |credits=, which produces label "Notable credit(s)"; or by |works=, which produces label "Works"; or by |label_name=, which produces label "Label(s)" -->
| notable_works = <!-- produces label "Notable work"; may be overridden by |credits=, which produces label "Notable credit(s)"; or by |works=, which produces label "Works"; or by |label_name=, which produces label "Label(s)" -->
| home_town =
| net_worth = <!-- Net worth should be supported with a citation from a reliable source -->
| net_worth = <!-- Net worth should be supported with a citation from a reliable source -->
| height = <!-- "X cm", "X m" or "X ft Y in" plus optional reference (conversions are automatic) -->
| height = <!-- "X cm", "X m" or "X ft Y in" plus optional reference (conversions are automatic) -->
Line 51: Line 51:
}}
}}
{{BLP primary sources|date=April 2017}}
{{BLP primary sources|date=April 2017}}
'''Raphael Linus Levien''' (also known as '''Raph Levien'''; born July 16, 1961) is a Dutch software developer, a member of the [[free software]] developer community, through his creation of the [[Advogato]] virtual community and his work with the free software branch of [[Ghostscript]]. From 2007 until 2018 he was employed at [[Google]].<ref name="levien.com|accessdate=7">{{cite web|last=Levien|first=Raphael|title=Personal Webpage|url=http://www.levien.com|access-date=7 April 2013}}</ref><ref name="new-adventure">{{cite web|last=Levien|first=Raphael|title=A New Adventure|url=https://raphlinus.github.io/personal/2018/08/28/a-new-adventure.html|access-date=28 August 2018|date=2018-08-28}}</ref> He holds a [[PhD]] in Computer Science from [[UC Berkeley]].<ref name="levien.com">{{cite journal|url = http://www.levien.com/phd/elastica_hist.pdf|title = The elastica: a mathematical history|date = 23 August 2008|access-date = 2011-08-04}}</ref> He also made a [[computer-assisted proof]] system similar to [[Metamath]]: [https://github.com/google/ghilbert Ghilbert]. In April 2016, Levien announced a text editor made as a "[[20% Project]]" (Google allows some employees to spend 20% of their working hours developing their own projects): [https://github.com/google/xi-editor Xi].
'''Raphael Linus Levien''' (also known as '''Raph Levien'''; born April 6, 1970) is a software developer, a member of the [[free software]] developer community, through his creation of the [[Advogato]] virtual community and his work with the free software branch of [[Ghostscript]]. From 2007 until 2018, and from 2021 onwards, he was employed at [[Google]].<ref name="levien.com|accessdate=7"/><ref name="new-adventure">{{cite web|last=Levien|first=Raphael|title=A New Adventure|url=https://raphlinus.github.io/personal/2018/08/28/a-new-adventure.html |website=Raph Levien’s blog |access-date=28 August 2018|date=2018-08-28}}</ref><ref>{{Cite web|title=Raph Levien (@raphlinus) |website= Twitter |url=https://twitter.com/raphlinus|archive-url=https://web.archive.org/web/20210120093224/https://twitter.com/raphlinus|archive-date=2021-01-20|access-date=2021-09-03}}</ref> He holds a [[PhD]] in Computer Science from [[UC Berkeley]].<ref name="levien.com">{{cite web |url = http://www.levien.com/phd/elastica_hist.pdf |first1=Raph |last1=Levien |title = The elastica: a mathematical history|date = 23 August 2008|access-date = 2011-08-04 |url-status=dead |archive-url= https://web.archive.org/web/20110927104721/http://www.levien.com/phd/elastica_hist.pdf |archive-date= Sep 27, 2011 }}</ref> He also made a [[computer-assisted proof]] system similar to [[Metamath]]: [https://github.com/google/ghilbert Ghilbert]. In April 2016, Levien announced a text editor made as a "[[20% Project]]" (Google allows some employees to spend 20% of their working hours developing their own projects): [https://github.com/xi-editor/xi-editor Xi].


==Imaging and typography==
==Imaging and typography==
The primary focus of Levien's work and research is in the varied areas regarding the theory of imaging—that is, rendering pictures and fonts for electronic display, which in addition to being aesthetically and mathematically important also contribute to the accessibility and search-openness of the web.
The primary focus of Levien's work and research is in the varied areas regarding the theory of imaging—that is, rendering pictures and fonts for electronic display, which in addition to being aesthetically and mathematically important also contribute to the accessibility and search-openness of the web.


Levien has written several papers documenting his research in [[Halftone|halftoning]] technology, which have been implemented in the [[Gimp-Print]] free software package, as well as by several commercial implementations. He also created Gill, the [[GNOME|GNOME desktop]] illustration application which aimed at supporting the W3C [[Scalable Vector Graphics|SVG]] standard for Vector Graphics. He states it was named after [[Eric Gill]], the English type designer responsible for the [[Gill Sans]], [[Perpetua (typeface)|Perpetua]] and [[Joanna (typeface)|Joanna]] fonts. Direct development on Gill ceased around the year 2000, but a [[Fork (software development)|fork]] of its codebase has evolved to [[Sodipodi]], and through it to [[Inkscape]].
Levien has written several papers documenting his research in [[Halftone|halftoning]] technology, which has been implemented in the [[Gimp-Print]] free software package, as well as by several commercial implementations. He also created Gill, the [[GNOME|GNOME desktop]] illustration application which aimed at supporting the W3C [[Scalable Vector Graphics|SVG]] standard for Vector Graphics. He states it was named after [[Eric Gill]], the English type designer responsible for the [[Gill Sans]], [[Perpetua (typeface)|Perpetua]] and [[Joanna (typeface)|Joanna]] fonts. Direct development on Gill ceased around the year 2000, but a [[Fork (software development)|fork]] of its codebase has evolved to [[Sodipodi]], and through it to [[Inkscape]].


In 2009, Levien completed a PhD thesis entitled 'From Spiral to Spline: Optimal Techniques in Interactive Curve Design'<ref name="Levien">{{cite web|last= Levien |first= Raphael |title= From Spiral to Spline: Optimal Techniques in Interactive Curve Design |url= http://www.levien.com/phd/phd.html |access-date= 18 September 2011 }}</ref> and published a standalone essay on the mathematical history of [[Elastica Theory|Elastica]].<ref name="levien.com"/> He calls the Elastica "A beautiful family of curves based on beautiful mathematics and a rich and fascinating history."
In 2009, Levien completed a PhD thesis entitled 'From Spiral to Spline: Optimal Techniques in Interactive Curve Design'<ref name="Levien">{{cite web|last= Levien |first= Raphael |title= From Spiral to Spline: Optimal Techniques in Interactive Curve Design |url= http://www.levien.com/phd/phd.html |access-date= 18 September 2011 }}</ref> and published a standalone essay on the mathematical history of [[Elastica Theory|Elastica]].<ref name="levien.com"/> He calls the Elastica "A beautiful family of curves based on beautiful mathematics and a rich and fascinating history."


Beginning in 2010, his work with Google largely focused on introducing high-quality, open licensed, well organized webfonts to the internet through Google's webfont API.<ref>{{cite web|title=Google I/O 2011 Webfonts Presentations|url=https://www.youtube.com/watch?v=QTX1lU97z08|publisher=YouTube|access-date=18 September 2011}}</ref> Here, his experience with typographical technology, history and industry<ref name="Levien"/> helped to shape the development of this growing resource, though he has since moved on from the project to work on Android fonts and text layout.<ref name="levien.com|accessdate=7"/>
Beginning in 2010, his work with Google largely focused on introducing high-quality, open licensed, well organized webfonts to the internet through Google's webfont API.<ref>{{cite AV media|title=Google I/O 2011 Webfonts Presentations|url=https://www.youtube.com/watch?v=QTX1lU97z08 |archive-url=https://ghostarchive.org/varchive/youtube/20211212/QTX1lU97z08| archive-date=2021-12-12 |url-status=live|publisher=YouTube|access-date=18 September 2011}}{{cbignore}}</ref> Here, his experience with typographical technology, history and industry<ref name="Levien"/> helped to shape the development of this growing resource, though he has since moved on from the project to work on Android fonts and text layout.<ref name="levien.com|accessdate=7"/>


One of his own fonts, [[Inconsolata]] (named in 2009 as one of the ten best programming fonts by Hivelogic,<ref>{{cite web|last=Benjamin|first=Dan|title=Top 10 Programming Fonts|url=http://hivelogic.com/articles/top-10-programming-fonts/|publisher=Hivelogic|access-date=18 September 2011}}</ref> and generally known for its clean lines and elegant design) is now available within the Google library.<ref>{{cite web|last=Levien|first=Raphael|title=Inconsolata|url=http://www.google.com/webfonts/specimen/Inconsolata|work=Webfont API|access-date=18 September 2011}}</ref> Regarding this font and his curves work in general, Levien had to say, "And, in fact, I don't just use the [[Euler spiral]]s, I use a mixture of curves (my package is called Spiro, which is kind of an abbreviation for polynomial spirals). Most of Inconsolata (the monospaced font mentioned above) is drawn using G4-continuous splines, which are a very close approximation to the Minimum Variation Curve of Henry Moreton. I now think that's overkill, and G2-continuous splines (the Euler spiral ones) are plenty, and could be done with fewer points." <ref name="levien.com|accessdate=7"/>
One of his own fonts, [[Inconsolata]] (named in 2009 as one of the ten best programming fonts by Hivelogic,<ref>{{cite web|last=Benjamin|first=Dan|title=Top 10 Programming Fonts|url=http://hivelogic.com/articles/top-10-programming-fonts/|publisher=Hivelogic|access-date=18 September 2011}}</ref> and generally known for its clean lines and elegant design) is now available within the Google library.<ref>{{cite web|last=Levien|first=Raphael|title=Inconsolata|url=http://www.google.com/webfonts/specimen/Inconsolata|work=Webfont API|access-date=18 September 2011}}</ref> Regarding this font and his curves work in general, Levien had to say, "And, in fact, I don't just use the [[Euler spiral]]s, I use a mixture of curves (my package is called Spiro, which is kind of an abbreviation for polynomial spirals). Most Inconsolata (the monospaced font mentioned above) is drawn using G4-continuous splines, which are a very close approximation to the Minimum Variation Curve of Henry Moreton. I now think that's overkill, and G2-continuous splines (the Euler spiral ones) are plenty, and could be done with fewer points."<ref name="levien.com|accessdate=7"/>


==Advogato==
==Advogato==
In November 1999, Levien founded [[Advogato]], a social website for the [[free software]] community, to test his ideas of [[attack-resistant trust metric]]s and to provide a development-focused forum for the free software community that was free of the kind of commercial motivations of such sites as [[Sourceforge]].
In November 1999, Levien founded [[Advogato]], a social website for the [[free software]] community, to test his ideas of [[attack-resistant trust metric]]s and to provide a development-focused forum for the free software community that was free of the kind of commercial motivations of such sites as [[SourceForge]].


The site has been successful from the point of view of the first criterion, surviving many attacks aimed at subverting the attack metric, made both by developers trying out attacks, and by [[Spam (electronic)|spam]]mers. The site has needed only relatively minor changes to cope with these. The site's trust metric provides, alongside [[Epinions]], one of the two most important datasets used in empirical analysis of trust metrics and [[reputation system]]s. Levien observed that [[Google]]'s [[PageRank]] algorithm can be understood to be an attack resistant trust metric rather similar to that behind Advogato.<ref>Chapter six of (Levien 2006).</ref>
The site has been successful from the point of view of the first criterion, surviving many attacks aimed at subverting the attack metric, made both by developers trying out attacks, and by [[Spam (electronic)|spam]]mers. The site has needed only relatively minor changes to cope with these. The site's trust metric provides, alongside [[Epinions]], one of the two most important datasets used in the empirical analysis of trust metrics and [[reputation system]]s. Levien observed that [[Google]]'s [[PageRank]] algorithm can be understood to be an attack-resistant trust metric rather similar to that behind Advogato.<ref>Chapter six of (Levien 2006).</ref>


The site has had a more rocky road as a forum for free software developers, and currently{{when|date=October 2014}} hosts less discussion than at its peak as developers have moved from forums to [[weblog]]s. Due to this, Advogato has added a syndication feature which includes the weblogs of its current certified developer base. It remains one of the earlier networking sites, and is still a place for active discussion on development of free software.
The site has had a more rocky road as a forum for free software developers, and currently{{when|date=October 2014}} hosts less discussion than at its peak as developers have moved from forums to [[weblog]]s. Due to this, Advogato has added a syndication feature that includes the weblogs of its current certified developer base. It remains one of the earlier networking sites and is still a place for active discussion on the development of free software.


==Activism in GPL-licensed software and encryption legislation==
==Activism in GPL-licensed software and encryption legislation==
Levien played a small part in precipitating the relaxation of the US [[Export of cryptography#PC era|crypto export legislation]], by filing for a [https://web.archive.org/web/20050316074605/http://www.petting-zoo.net/~deadbeef/archive/340.html Commodities Jurisdiction Request] for a T-shirt containing an implementation of the [[RSA (algorithm)|RSA]] encryption algorithm, in four lines of [[Perl]]. At the time (1995), the code on the T-shirt would have been regarded as a [[munition]] by the [[United States]] and other [[NATO]] governments.
Levien played a small part in precipitating the relaxation of the US [[Export of cryptography#PC era|crypto export legislation]], by filing for a [https://web.archive.org/web/20050316074605/http://www.petting-zoo.net/~deadbeef/archive/340.html Commodities Jurisdiction Request] for a [[T-shirt]] containing an implementation of the [[RSA (algorithm)|RSA]] encryption algorithm, in four lines of [[Perl]]. At the time (1995), the code on the T-shirt would have been regarded as a [[munition]] by the [[United States]] and other [[NATO]] governments.


ZD-Net's ''Interactive week'' summarised the issue that patents pose to the free software community:<ref name="in-1">Peter Wayner, ZD-Net ''Interactive Weel'', 8 November 2001. Levien provided [http://www.levien.com/wayner-patch.html an annotated summary] of the article.</ref>
ZD-Net's ''Interactive week'' summarised the issue that patents pose to the free software community:<ref name="in-1">Peter Wayner, ZD-Net ''Interactive Weel'', 8 November 2001. Levien provided [http://www.levien.com/wayner-patch.html an annotated summary] of the article.</ref>
:''Levien recognizes the paradox: On one hand, he made money from forcing everyone who used his patented ideas to give him royalties. On the other, he shared the source code of several programs and recognized how the cooperation helped him and others. The two models were in conflict.''
{{blockquote|Levien recognizes the paradox: On one hand, he made money from forcing everyone who used his patented ideas to give him royalties. On the other, he shared the source code of several programs and recognized how the cooperation helped him and others. The two models were in conflict.}}


As a resolution to this conflict, in March 2000, Levien made a [http://www.advogato.org/article/89.html patent grant] of his [[patent portfolio]] to the GPL community.
As a resolution to this conflict, in March 2000, Levien made a [http://www.advogato.org/article/89.html patent grant] of his [[patent portfolio]] to the GPL community.


==Personal life==
==Personal life==
He is divorced, with two sons: Alan and Max, and a stepdaughter. He is a member of the [[Berkeley, California|Berkeley]] Monthly Meeting<ref>{{cite web|url=http://www.quaker.org/berkmm/ |title=Berkeley Monthly Meeting website |publisher=Quaker.org |date=2013-09-11 |access-date=2013-12-05}}</ref> of the [[Religious Society of Friends (Quakers)]].<ref>{{cite web|url=http://www.levien.com/ |title=Personal website |publisher=Levien.com |access-date=2013-12-05}}</ref> In the book ''TeX People: Interviews from the world of [[TeX]]'', Levien notes, "I was born in [[Enkhuizen]], the Netherlands, and moved to Virginia when I was three, so I don't really speak Dutch or anything but I do find myself with a liking for herring."<ref>{{cite book|last=Tex|title=TeX People: Interviews from the world of TeX|year=2009|publisher=TeX|isbn=978-0982462607|url=http://tug.org/interviews/levien.pdf}}</ref>
He is divorced, with two sons: Alan and Max. He is a member of the [[Berkeley, California|Berkeley]] Monthly Meeting<ref>{{cite web|url=https://www.berkeleyfriendsmeeting.org/ |title=Berkeley Monthly Meeting website |date=2022-07-20 |access-date=2022-07-20}}</ref> of the [[Religious Society of Friends (Quakers)]].<ref name="levien.com|accessdate=7">{{cite web|url=http://www.levien.com/ |title=Raph Levien |publisher=Levien.com |access-date=2013-12-05 |url-status=unfit |archive-url=https://web.archive.org/web/20130410060622/http://www.levien.com/ |archive-date= Apr 10, 2013 }}</ref> In the book ''TeX People: Interviews from the world of [[TeX]]'', Levien notes, "I was born in [[Enkhuizen]], the Netherlands, and moved to Virginia when I was three, so I don't really speak Dutch or anything but I do find myself with a liking for herring."<ref>{{cite book|last=Tex|title=TeX People: Interviews from the world of TeX|year=2009|publisher=TeX|isbn=978-0982462607|url=http://tug.org/interviews/levien.pdf}}</ref>


==Bibliography==
==Bibliography==
Line 98: Line 98:


{{DEFAULTSORT:Levien, Raph}}
{{DEFAULTSORT:Levien, Raph}}
[[Category:1961 births]]
[[Category:1970 births]]
[[Category:Living people]]
[[Category:Living people]]
[[Category:Free software programmers]]
[[Category:Free software programmers]]

Latest revision as of 05:08, 5 May 2024

Raph Levien
Born1970 (age 53–54)
Enkhuizen, Netherlands
CitizenshipAmerican
Alma materUniversity of California, Berkeley
OccupationProgrammer
EmployerGoogle
Known forAdvogato
Children2
Websitewww.levien.com

Raphael Linus Levien (also known as Raph Levien; born April 6, 1970) is a software developer, a member of the free software developer community, through his creation of the Advogato virtual community and his work with the free software branch of Ghostscript. From 2007 until 2018, and from 2021 onwards, he was employed at Google.[1][2][3] He holds a PhD in Computer Science from UC Berkeley.[4] He also made a computer-assisted proof system similar to Metamath: Ghilbert. In April 2016, Levien announced a text editor made as a "20% Project" (Google allows some employees to spend 20% of their working hours developing their own projects): Xi.

Imaging and typography[edit]

The primary focus of Levien's work and research is in the varied areas regarding the theory of imaging—that is, rendering pictures and fonts for electronic display, which in addition to being aesthetically and mathematically important also contribute to the accessibility and search-openness of the web.

Levien has written several papers documenting his research in halftoning technology, which has been implemented in the Gimp-Print free software package, as well as by several commercial implementations. He also created Gill, the GNOME desktop illustration application which aimed at supporting the W3C SVG standard for Vector Graphics. He states it was named after Eric Gill, the English type designer responsible for the Gill Sans, Perpetua and Joanna fonts. Direct development on Gill ceased around the year 2000, but a fork of its codebase has evolved to Sodipodi, and through it to Inkscape.

In 2009, Levien completed a PhD thesis entitled 'From Spiral to Spline: Optimal Techniques in Interactive Curve Design'[5] and published a standalone essay on the mathematical history of Elastica.[4] He calls the Elastica "A beautiful family of curves based on beautiful mathematics and a rich and fascinating history."

Beginning in 2010, his work with Google largely focused on introducing high-quality, open licensed, well organized webfonts to the internet through Google's webfont API.[6] Here, his experience with typographical technology, history and industry[5] helped to shape the development of this growing resource, though he has since moved on from the project to work on Android fonts and text layout.[1]

One of his own fonts, Inconsolata (named in 2009 as one of the ten best programming fonts by Hivelogic,[7] and generally known for its clean lines and elegant design) is now available within the Google library.[8] Regarding this font and his curves work in general, Levien had to say, "And, in fact, I don't just use the Euler spirals, I use a mixture of curves (my package is called Spiro, which is kind of an abbreviation for polynomial spirals). Most Inconsolata (the monospaced font mentioned above) is drawn using G4-continuous splines, which are a very close approximation to the Minimum Variation Curve of Henry Moreton. I now think that's overkill, and G2-continuous splines (the Euler spiral ones) are plenty, and could be done with fewer points."[1]

Advogato[edit]

In November 1999, Levien founded Advogato, a social website for the free software community, to test his ideas of attack-resistant trust metrics and to provide a development-focused forum for the free software community that was free of the kind of commercial motivations of such sites as SourceForge.

The site has been successful from the point of view of the first criterion, surviving many attacks aimed at subverting the attack metric, made both by developers trying out attacks, and by spammers. The site has needed only relatively minor changes to cope with these. The site's trust metric provides, alongside Epinions, one of the two most important datasets used in the empirical analysis of trust metrics and reputation systems. Levien observed that Google's PageRank algorithm can be understood to be an attack-resistant trust metric rather similar to that behind Advogato.[9]

The site has had a more rocky road as a forum for free software developers, and currently[when?] hosts less discussion than at its peak as developers have moved from forums to weblogs. Due to this, Advogato has added a syndication feature that includes the weblogs of its current certified developer base. It remains one of the earlier networking sites and is still a place for active discussion on the development of free software.

Activism in GPL-licensed software and encryption legislation[edit]

Levien played a small part in precipitating the relaxation of the US crypto export legislation, by filing for a Commodities Jurisdiction Request for a T-shirt containing an implementation of the RSA encryption algorithm, in four lines of Perl. At the time (1995), the code on the T-shirt would have been regarded as a munition by the United States and other NATO governments.

ZD-Net's Interactive week summarised the issue that patents pose to the free software community:[10]

Levien recognizes the paradox: On one hand, he made money from forcing everyone who used his patented ideas to give him royalties. On the other, he shared the source code of several programs and recognized how the cooperation helped him and others. The two models were in conflict.

As a resolution to this conflict, in March 2000, Levien made a patent grant of his patent portfolio to the GPL community.

Personal life[edit]

He is divorced, with two sons: Alan and Max. He is a member of the Berkeley Monthly Meeting[11] of the Religious Society of Friends (Quakers).[1] In the book TeX People: Interviews from the world of TeX, Levien notes, "I was born in Enkhuizen, the Netherlands, and moved to Virginia when I was three, so I don't really speak Dutch or anything but I do find myself with a liking for herring."[12]

Bibliography[edit]

References[edit]

  1. ^ a b c d "Raph Levien". Levien.com. Archived from the original on Apr 10, 2013. Retrieved 2013-12-05.{{cite web}}: CS1 maint: unfit URL (link)
  2. ^ Levien, Raphael (2018-08-28). "A New Adventure". Raph Levien’s blog. Retrieved 28 August 2018.
  3. ^ "Raph Levien (@raphlinus)". Twitter. Archived from the original on 2021-01-20. Retrieved 2021-09-03.
  4. ^ a b Levien, Raph (23 August 2008). "The elastica: a mathematical history" (PDF). Archived from the original (PDF) on Sep 27, 2011. Retrieved 2011-08-04.
  5. ^ a b Levien, Raphael. "From Spiral to Spline: Optimal Techniques in Interactive Curve Design". Retrieved 18 September 2011.
  6. ^ Google I/O 2011 Webfonts Presentations. YouTube. Archived from the original on 2021-12-12. Retrieved 18 September 2011.
  7. ^ Benjamin, Dan. "Top 10 Programming Fonts". Hivelogic. Retrieved 18 September 2011.
  8. ^ Levien, Raphael. "Inconsolata". Webfont API. Retrieved 18 September 2011.
  9. ^ Chapter six of (Levien 2006).
  10. ^ Peter Wayner, ZD-Net Interactive Weel, 8 November 2001. Levien provided an annotated summary of the article.
  11. ^ "Berkeley Monthly Meeting website". 2022-07-20. Retrieved 2022-07-20.
  12. ^ Tex (2009). TeX People: Interviews from the world of TeX (PDF). TeX. ISBN 978-0982462607.

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Raph_Levien&oldid=1222299133"