Mayer, Frederick
American Book Company, 1951
Buku Klasik
Kenny
Oxford University Press, 2008
Buku Teks SO
Hoffding, Harold
Macmillan, 1955
Buku Teks SO
Bertens, Kees
Daras, 2005
Buku Teks SO
Brouwer, Martinus Antonius Wesselinus, 1923-
Alumni, 1986
Buku Teks SO