Banerji, Hrishikes, author
Universities Foundation, 1956
Buku Teks
Krooss, Herman Edward, 1912-1975, author
Prentice-Hall, 1966
Buku Teks
Cypher, James M., author
Routledge, 1997
Buku Teks
Moulton, Harold G., author
Brookings Institution, 1935
Buku Teks
edited by Leonard H. Goodman
Columbia University Press, 1966
Buku Teks