Macpherson, Gavin
Longman, 1993
Buku Teks
Kingma, Bruce R.
Libraries Unlimited, Inc., 1996
Buku Teks SO
Mishan, Ezra J.
George Allen and Unwin, 1976
Buku Teks SO
Mishan, Ezra J.
Routledge, 1972
eBooks
Ray, Anandarup
John Hopkins University Press, 1984
Buku Teks SO