edited by Bruce W. Burkhart and Wesley S. Thompson
Burgess Publishing, 1972
Buku Teks
Eiser, Arthur L., author
Burgess , 1970
Buku Teks
Seidman, Lisa A., author
Prentice-Hall, 2000
Buku Teks
Williams, Thomas Rhys
Holt, Rinehart and Winston, 1967
Buku Teks
MacDonald, Pia D.M., author
Jones & Bartlett Learning, 2012
Buku Teks