Kelley, Donald R., author
Harvard University Press, 1990
Buku Teks
Newhauser, Richard
Ashgate/Variorum, 2007
Buku Teks
Weber, Eugen, author
Boston: D.C.Heath and Company, (1959).
Buku Teks
Harris, Roy, author
Routledge, 1997
Buku Teks
Sakyejul Publ, 2005
Buku Teks