Gibson, Stuart W., author
Mac Millan Press , 1994
Buku Teks
Chayen, J., author
John Wiley & Sons, 1972
Buku Teks
Terribile, Mark A., author
Prentice-Hall, 1993
Buku Teks
Jones, R.N., author
John Wiley & Sons, 1990
Buku Teks
Barker, D.J.P., author
Livingstone, 1976
Buku Teks