Prakash, Om, author
Frederick A. Praeger, 1962
Buku Teks
Nowak, Norman D., author
Praeger, 1970
Buku Teks
Palvia, Chand Mal
Institute of Social Studies, 1953
Buku Teks
Chelliah, Raja Jesudoss.
Allen & Unwin, 1969
Buku Teks
Kashkari, Chaman.
McGraw-Hill, 1975.
Buku Teks