edited by Egbert De Vries, Jose Medina Echavarria
UNESCO, 1967
Buku Teks
Cole, J.P., author
Butterworth, 1965
Buku Teks
Stein, Stanley J., author
Oxford University Press, 1970
Buku Teks
Echavarria, Jose Medina, author
New York, N.Y., Unesco
Buku Teks
Gordon, Lincoln, author
Harvard University Press, 1963
Buku Teks