Guandola, M.H.
Merriam & Webster, INC, 1989
Buku Teks
Garner, Bryan A., author
Oxford University Press, 1995
Buku Referensi
Salman, S.L., author
S.S. Mubaruk and Brothers, 1994
Buku Teks
Mellinkoff, David, author
[Publisher not identified], 1992
Buku Teks
London: Tiger Books International, 1994,
Buku Referensi