Green, D.C.
Longman, 1988
Buku Teks
Hamzah Berahim,
Andi, 1996
Buku Teks
Green, D.C.
Longman Scientific & Tecnical, 1992
Buku Teks
Woodruff, L.F.
Wiley Eastern, 1938
Buku Teks
editor, Milton Kaufman, Arthur H. Seidman
McGraw-Hill, 1984
Buku Referensi