Corsini, Raymond J., author
Brunner-Routledge, 2002
Buku Teks
Collin, P. H., author
Peter Collin Publishing, 2001
Buku Teks
Pei, Mario A., author
Philosophical Library, 1954
Buku Referensi
Pei, Mario A., author
Totowa, New Jersey Littlefield, Adams 1975
Buku Referensi
Wales, Katie, author
Longman , 1991
Buku Referensi