editor, Kirk J. Schneider, James F.T. Bugental, J. Fraser Pierson
Sage, 2001
Buku Referensi
DeCarvalho, Roy Jose
Praeger , 1991
Buku Teks SO
[edited by] Elaine Lynne La Monica
Wadsworth Health Sciences Division, 1985
Buku Teks SO
edited by Edmund A. Bowles
Prentice-Hall, 1967
Buku Teks SO
Schultz, Duane
D. Van Nostrand Company, 1977
Buku Teks SO