Leland, Karen
IDG Books Worldwide, 1996
Buku Teks
Pickle, Hal B., author
John Wiley & Sons, 1984
Buku Teks
Steinhoff, Dan, author
McGraw-Hill, 1978
Buku Teks
Sondeno, Stanley R., author
Business Publications, 1985
Buku Teks
Harper & Row, 1975
Buku Teks