Perlman, Selig History of Labour in the United States Vol. 2
Book by John B. Andrews, John R. Commons, H. E. Hoagland, E. B. Mittelman, Selig Perlman, David J. Saposs, Helen L. Sumner; Macmillan, 1918
Perry, Ralph The Moral Economy
Book by Ralph Barton Perry; Charles Scribner's Sons, 1909
Perry, Ralph The New Realism: Cooperative Studies in Philosophy
Book by Edwin B. Holt, Walter T. Marvin, William Pepperrell Montague, Ralph Barton Perry, Edward Gleason Spaulding; Macmillan Company, 1912
Petrunkevitch, Alexander The Russian Revolution
Book by Frank Alfred Golder, Samuel Northrup Harper, Robert Joseph Kerner, Alexander Petrunkevitch; Harvard University Press, 1918
Phillimore, J. English Literature and the Classics
Book by A. C. Clark, H. W. Garrod, A. D. Godley, G. S. Gordon, G. S. Gordon, Gilbert Murray, S. G. Owen, J. S. Phillimore, J. A. Stewart, J. E. Tiddy; The Clarendon Press, 1912
Proctor, Richard Essays in Astronomy
Book by Sir Robert S. Ball, William Harkness, Sir John Herschel, Edward Singleton Holden, William Huggins, Marquid de Laplace, Ormsby McKnight Mitchel, Richard Proctor, M. Schiaparelli; D. Appleton & Company, 1900