Foster, George M., author
Brown and Comp, 1969
Buku Teks
Chambers, Erve, author
Waveland Press, 1989
Buku Teks
Ferraro, Gary P., author
Cengage Learning, 2018
Buku Teks
Ferraro, Gary P., author
Delmar Cengage Learning, 2014
Buku Teks
Ember, Carol R., author
Prentice-Hall, 1985
Buku Teks