Mcnulty, John K.
West Publishing Company, 1972
Buku Teks
Burke, Karen C.
Thomson/West, 1999
Buku Teks
Gaa, Charles J., author
McGraw-Hill , 1965
Buku Referensi
Gaa, Charles J., author
McGraw-Hill , 1965
Buku Referensi
Rowlands, Graham, author
MAKAR, 1972
Buku Teks