Hussain, K.M.
Organization for Economic Co-operation and Development , 1976
Buku Teks
Departemen Pendidikan dan Kebudayaan, 1980
Buku Teks
Center for International Higher Education Boston Collage,
Majalah, Jurnal, Buletin
The University , Iowa City, 1912
Buku Klasik
Prentice-Hall, 1960
Buku Teks