edited by Cranley Onslow
Frederick A. Praeger, 1965
Buku Teks
Badgley, John H., author
The Free Press, 1971
Buku Teks
edited by Yogesh Atal and Ralph Pieris
Abhinav Publications, 1976
Buku Teks
Land, Ray, author
Open University Press, 2004
Buku Teks
Harbison, Frederick Harris, author
International Institute for Educational Planning Unesco , 1967
Buku Teks