Stegeman, Cynthia A..
Elsevier Saunder, 2015
Buku Teks
Drago, Carl
Blackwell Publishing, 2007
Buku Referensi
Ziegler, Kathleen
Rockport Publishers, 1994
Buku Referensi
Drago, Carl
Blackwell, 2014
Buku Teks
Jackson, Paul
Chancellor, 1994
Buku Referensi