Sage Publications, 2009
eBooks
Bouvier, Leon F., author
Seven Lucks Press, 1999
Buku Teks
The Haworth Press, 1991
Buku Teks
Ruth Chadwick, Henk ten Have and Eric M. Meslin
Sage, 2011
Buku Teks
Pearman, William A. and Starr, Philip
New York : Garland Publishing, 1988,
Buku Referensi