Bernardo, Francisco P.
Asian Productivity Organization, 1972
Buku Teks
Arnold, Pauline
Holiday House , 1963
Buku Teks
Barwell, F.T., author
Pergamon Press, 1983
Buku Teks
Einzig, Paul
Eyre & Spottiswood , 1949
Buku Teks
Merkulov, A.
Foreign Languages Publishing House,
Buku Teks