Evers, Hans-Dieter, author
LP3ES, [19..]
Buku Teks
Elias, C.E. Jr
Wadsworth, 1965
Buku Teks
Gans, Herbert J., author
The Free Press, 1982
Buku Teks
Marbun, B.N. (Benedictus Nahot), author
Erlangga, 1979
Buku Teks
Oxford University Press, 1973
Buku Teks