edited by Egbert De Vries, Jose Medina Echavarria
UNESCO, 1967
Buku Teks
Powelson, John P.
McGraw-Hill , 1964
Buku Teks
Powelson, John P.
McGraw-Hill , 1964
Buku Teks
edited by Howard S. Ellis and Henry C. Wallich
Macmillan, 1963
Buku Teks
Thurber, Glarence E
Duke University Press, 1973
Buku Teks