The World bank, 2007
Buku Teks
Flexner, Abraham
Oxford University Press, 1968
Buku Teks
edited by Monbusho
Maruzen, 1985
Buku Referensi
Tapingkae, Amnuay
Regional Institute of Higher Education and Development, 1974
Buku Teks
O`Leary, John, author
QS Quacquarelli Symonds Limited, 2010
Buku Referensi