Evans, Graham, author
Harvester Wheatsheaf, 1990
Buku Referensi
Lewis, Norman, author
Harper & Row , 1962
Buku Referensi
edited by Michael W. Alssid and William Kenney
Halt, Rinchart and Winston, 1964
Buku Teks
Mitchell, H.B., author
[Springer, Springer], 2012
eBooks
Magstadt, Thomas M., author
Wadsworth-Cengage learning, 2009
Buku Teks