Sharma, Ram Sharan, author
Motilal Banarsidass , 1991
Buku Teks
Hardgrave, Robert L., author
Harcourt, Brace, 1970
Buku Teks
Sharan, P.
Metropolitan, 1984
Buku Teks
Hardgrave, Robert L., author
Harcourt College, 2000
Buku Teks
Palmer, Norman D.
Houghton Mifflin, 1961
Buku Teks