Bowser, eileen, author
Macmillan Library reference USA, 1990
Buku Referensi
Otto, Henry J.
Aplenton-Century-Crofts, 1964
Buku Teks
Tudisco, A.J.
Diablo Press, 1964
Buku Teks
Addison-wesley, 1982
Buku Teks
Cheng, David C.
Addison-Wesley , 1979
Buku Teks