Matherson, Ross, author
John Wiley & Sons, 1978
Buku Teks
Saksena, K.P., author
Sage, 1986
Buku Teks
by Robert E. Asher ... [and others]
Brookings Institution, 1962
Buku Teks
by Economic and Social Comission for Asia and the Pacific, United Nations
United Nations, 1983
Buku Teks
Sie, Kwat Soen
Centre for Agricultural Publications and Documentation, 1968
Buku Teks