edited by Donald R. Lessar
John Wiley & Sons, 1985
Buku Teks
Hersey, Paul, author
Pearson, Prentice Hall, 2008
Buku Teks
Adam, Everett E., author
Prentice-Hall, 1982
Buku Teks
Adam, Everett E., author
Prentice-Hall, c1986
Buku Teks
Scanlan, Burt
John Wiley & Sons, 1983
Buku Teks