edited by James Petras
John Wiley & Sons, 1973
Buku Teks
De Vos, George A.
University of California Press, 1973
Buku Teks
edited by Mihaela Czobor-Lupp and J. Stefan Lupp
Council for Research in Values and Philosophy, 2002
Buku Teks
Gregg, Pauline, author
George G. Harrap, 1952
Buku Teks
Insor, D., author
Frederick A.Praeger, 1963
Buku Teks