Smith, Mike, author
Kyle Cathie Limited, 1994
Buku Referensi
Smith, Robert J.
Stanford Univerisity Press, 1974
Buku Teks
Szasz, F.A., author
John Wiley & Sons, 1981
Buku Teks
Wilde, W.H., author
Oxford University Press, 1969
Buku Teks
Cowan, Henry J., author
Van Nostrand Reinhold Company, 1983
Buku Teks