Reynolds, Paul Davidson
Prentice-Hall, 1982
Buku Teks SO
Gideon Sjoberg
Schenkman publishing Company, Inc., 1971
Buku Teks SO
Schenkman publishing Company, Inc., 1971
Buku Teks SO
Homan, Roger
Longman, 1991
Buku Teks SO
edited by Sugata Dasgupta
Impex India, 1967
Buku Teks SO