Dobson, Alan
Routledge, 2017
eBooks
Edited by William James
Anmol Publications PVT. LTD., 2005
Buku Teks
Humprey, Nicholas
New York Springer-Verlag , 1999
Buku Teks SO
Colbert, Edwin H.
John Wiley & Sons, 1980
Buku Teks
Saigon : Review Horizons, t.th.
Buku Teks