Muchinsky, Paul M., author
Wadsworth, 2000
Buku Teks
Oxford Universikty Press , 1956
Buku Teks
Aamodt, Michael G., author
Cengage Learning, 2016
Buku Teks
Gilmer, B. von Haller (Beverly von Haller), 1909-1994, author
McGraw-Hill, 1977
Buku Teks
Bass, Bernard M., author
Allyn and Bacon, 1973
Buku Teks