Ehrlich, Paul R.
Macmillan, 1987
Buku Teks SO
Forman, Richard T.T.
Cambridge University Press, 2014
Buku Teks SO
Henry W. Art, general editor ; foreword by F. Herbert Bormann ; contributing editors, Daniel Botkin [and others]
Henry Holt, 1993
Buku Referensi
Kormondy, Edward J.
Prentice-Hall, 1976
Buku Teks SO
Krohne, David T.
Brook/Cole, 2001
Buku Teks SO