Ponsioen, J.A.
Mouton, 1969
Buku Teks SO
Farley, John E.
Prentice-Hall, 1987
Buku Teks SO
Morkuniene, Jurate
Council for Research in Values and Philosophy, 2004
Buku Teks SO
by Robert L. Hamblin ... [et al.]
Robert E. Krieger, 1978
Buku Teks SO
edited by John Kosa, Aaron Antonovskv and Irving Kenneth Zola
Harvard University Press, 1969
Buku Teks