Narr Verlag , 1978
Buku Teks
edited by Lim Teck Ghee and Vincent Lowe
Heinemann Educational Books,(ASIA), 1976
Buku Teks
McDonald, Stephen L.
The Brookings Institution , 1963
Buku Teks
New York : Pergamon , 1976
Buku Teks
editor, Muhammadi
Regional Institute of Higher Education and Development, 1977
Buku Teks