edited by William Wels
Lippincott Williams & Wilkins, 2003
Buku Teks
Berges, Steve
American Management Association, 2006
eBooks
Goncalves, Marcus
McGraw-Hill , 2000
Multimedia
Bobola, Daniel T.
Alpha Books, 1995
Buku Teks
Howard, Jenna
Pearson Education , 1994
Buku Teks