edited by John Field, Ronald J. Burke and Cary L. Cooper.
SAGE, 2013
Buku Referensi
edited by Clark Tibbitts and Wilma Donahue
Prentice-Hall, 1960
Buku Teks
Artikel Jurnal
Robert H. Binstock, Linda K. George, editor
Elsevier , 2011
Buku Teks
Sheppard, Harold L., author
Free Press, 1977
Buku Teks