Victor R. Preedy, editor
[, Wageningen Academic], 2012
eBooks
Begoun, Paula
Beginning Press, 2009
Buku Teks
Lonely planet, [date of publication not identified]
Buku Referensi
Carroll, Stephen J.
Dorling Kindersley , 1992
Buku Referensi
Belcher, Wendy Laura
Sage Publications, 2009
Buku Teks