Skolnik, Lisa, author
Rockport Publisher, 2001
Buku Referensi
Walsh, Joleen, author
J.B. Lippincott, 1987
Buku Teks
Anderson, Joyce I., author
American Management Association, 2007
eBooks
Rice, Robyn, author
Mosby , 1996
Buku Teks
Zang, Sheryl Mara, author
EGC, 2003
Buku Teks