El Khobar Muhaemin Nazech
Lembaga Penelitian Universitas Indonesia, 1994
UI - Laporan Penelitian
Blackman, William C.
CRC Lewis, 1996
Buku Teks
Brunner, Calvin R.
McGraw-Hill, 1993
Buku Referensi
Duah-Asante, D. Kofi
E & FN Spon, 1998
Buku Teks
Wentz, Charles A.
McGraw-Hill, 1995
Buku Teks