Mehta, J.K.
Caitanya Publishing House, 1967
Buku Teks
Blaug, Mark
Cambridge University Press, 1987
Buku Teks
Fox, Karl August, 1917-
John Wiley & Sons, 1968
Buku Teks
Bjornson, Gordon B.
Vantage Press , 1971
Buku Teks
by H.G. Johnson... [and others]
Macmillan, 1968
Buku Teks