Schweitzer, James A.
Butterworth, 1982
Buku Teks
Blanca Jimenez and Joan Rose, editor
CRC Press, Taylor & Francis Group, 2009
Buku Teks
Kanter, Jerome
Englewood Cliffs, N.J. Prentice-Hall 1992,
Buku Referensi
Kanter, Jerome
Prentice-Hall, 1992
Buku Teks
Roberts, Sue
Facet Publishing, 2004
Buku Teks