South, David W., author
McGraw-Hill , 1995
Buku Referensi
Mager, N. H., author
Prentice-Hall, 1975
Buku Referensi
Bay Books, 1986
Buku Referensi
editor, Rom Harre, Roger Lamb
Blackwell Reference, 1983
Buku Referensi
The MIT Press, 1987,
Buku Referensi