Etter, Delores Maria, 1947-
Benjamin/Cummings, 1987
Buku Teks SO
Davis, Gordon B.
McGraw-Hill, 1988
Buku Teks SO
Boyle, Thomas A.
Brooks/Cole, 1985
Buku Teks SO
Metcalf, Michael
Clarendon Press , 1985
Buku Teks SO
Page, Clive
Multi Media, 1985
Buku Referensi