edited by Michael M. Horowitz and Thomas M. Painter
Westview Press, 1986
Buku Teks
Baal, Jan van, author
Foris Publications, 1984
Buku Referensi
Lloyd, P.C
Frederick A. Praeger, 1968
Buku Teks
Mouton , 1957
Buku Teks
Hugo, Graeme J.
Gadjah Mada Univ. Press, 1981
Buku Teks