Dover Publications , 1971
Buku Teks
Mandell, Steven L., author
West Publishing Company, 1982
Buku Referensi
Mandell, Steven L., author
West Publishing Company, 1982
Buku Teks
Awad, Elias M., author
Prentice-Hall, 1966
Buku Teks
Floyd, Nancy A., author
1987
Buku Teks