by Charles R. Hopkins ... [et al.]
Glencoe Publishing, 1979
Buku Teks
edited by John Field, Ronald J. Burke and Cary L. Cooper.
SAGE, 2013
Buku Referensi
Leyson, B.W.
New York: E.P. Dutton, 1955
Buku Teks
Hooker, M. B., author
Oxford University Press, 1976
Buku Teks
Kemble, Celerie, author
Clarkson Potter, 2008
Buku Referensi