Brouwer, Martinus Antonius Wesselinus, 1923-
Alumni, 1986
Buku Teks SO
Mayer, Frederick
American Book Company, 1951
Buku Klasik
Hoffding, Harold
Dover, 1955
Buku Teks SO
Kenny
Oxford University Press, 2008
Buku Teks SO
Hoffding, Harold
Macmillan, 1955
Buku Teks SO