Finn, Paul
Oxford University Press, 1987
Buku Referensi
Brennan, Niall, 1918-2005
Hill Publishing, 1972
Buku Teks SO
Busch, Francis X.
The Bobbs-Merrill, 1957
Buku Teks
Duggan, Francis X
Twayne, 1966
Buku Teks
Curran, Ward S.
McGraw-Hill, 1970
Buku Teks