Mandell, Steven L., author
West Publishing Company, 1982
Buku Referensi
Foster, J. M.
Macdonald & Co, 1967
Buku Teks
Oualline, Steve.
O'Reilly & Associates, 1991
Buku Referensi
Edwards, Perry, author
Wadsworth, 1979
Buku Teks
Mandell, Steven L., author
West Publishing Company, 1982
Buku Teks