Hurt, R. Douglas, author
Garland Publishing, 1994
Buku Referensi
Bridson, Gavin D.R.
Gerland Publishing, Inc., 1994
Buku Teks
Kemp, Herman C., author
KITLV Press, 1990
Buku Referensi
Alexander-Frutschi, author
Stanford Research Institute, 1963
Buku Teks
Groenendael, Victoria M. Clara van, author
Foris Publications, 1987
Buku Referensi