McLemore, S Dale
Allyn and Bacon, 1983
Buku Teks
Epps, Edgar G.
Winthrop Publisher,INC, 1973
Buku Teks
Goodman, Mary Ellen
Addison-Wesley, 1952
Buku Teks SO
Banton Michael
Tavistock Publications, 1969
Buku Teks
Mason, Philip
Oxford University Press, 1970
Buku Teks