DeVane, William Clyde, author
Harvard University Press, 1965
Buku Teks
Wiggins, Sam P.
McCutchan Publishing Corporation, 1966
Buku Teks
The International Association of Universities, 1995
Buku Referensi
Paris: The International Association of Universities, 1997
Buku Referensi
McGraw-Hill , 1973
Buku Teks