Ribble, Margaret A., author
Columbia University, 1958
Buku Teks
by Calvin S. Hall [and others]
John Wiley & Sons, 1985
Buku Teks
Cameron, Norman, author
Houghton Mifflin, 1963
Buku Teks
Monte, Christopher F., author
John Wiley & Sons, 2003
Buku Teks
edited by Linda L. Sperry and Patricia A. Smiley
Jossey-Bass, 1995
Buku Teks