Cargan, Leonard, author
Wadsworth, 1985
Buku Teks
Holt, Rinehart and Winston, 1985
Buku Teks
Huseman, Richard C., author
Allyn and Bacon, 1977
Buku Teks
Cummings, L.L., author
Richard D. Irwin, 1980
Buku Teks
edited by Gerald E. Caiden and Heinrich Siedentopf
LexingtonBooks, 1982
Buku Teks