Berry, Philippa
Routledge, 1999
Buku Teks
Humphrey, Thomas M.
Richmond, Va Federal Reserve Bank of Richmond, 1986
Buku Teks
Baxter, W.T.
Philip Allan , 1984
Buku Teks
Wilson, Thomas
Clarendon Press, 1984
Buku Teks
Kotwal, O. P.
McGraw-Hill, 1987
Buku Teks