Syjuco, Jose G.
Ne Day, 1977
Buku Teks
Sensarma, P.
Naya Prokash, 1977
Buku Teks
Fuller, John Frederick Charles
Funk and Wagnalls, 1955
Buku Teks
Grey, Jeffrey
Cambridge University Press, 1990
Buku Teks
by Peter Dennis, Jeffrey Grey, Ewan Morris, Robin Prior
Oxford University Press, 1995
Buku Referensi