Oliver, Daniel, author
Cambridge University Press , 2013
Buku Teks
Yapp, R.H, author
University Press, 1927
Buku Teks
Dutta, A.C., author
Oxford University Press, 1994
Buku Teks
Wilson, Carl L., author
Holt, Rinehart and Winston, 1962
Buku Teks
Neushul, Michael, author
Hamilton, 1974
Buku Teks