Brammer, Robert
Brooks/Cole Cengage Learning, 2012
Buku Teks
Choudhuri, Devika Dibya
Brooks/Cole Cengage Learning, 2012
Buku Teks
Arbuckle, Dugald S.
Allyn and Bacon, 1961
Buku Teks
editor, Don C. Locke, Jane E. Myers, Edwin L. Herr
Sage, 2001
Buku Referensi
Thompson, Charles L.
Broooks/Cole, 1996
Buku Teks SO