Warren, Carl S., author
South Western Cengage Learning, 2013
Buku Teks
Hinks, Arthur R., author
Cambridge Univ Press, 2014
Buku Teks
Sage, 2003
Buku Referensi
Fink, Arlene, author
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Vaughn, Donald E., author
Holt, Rinehart and Winston, 1967
Buku Teks