Capehart, Barney L.
The Fairmont Press, Inc., 2008
Buku Teks
O`Callaghan, P. W.
Pergamon Press, 1981
Buku Referensi
Reay, David A.
Pergamon Press, 1979
Buku Teks
Herkimer, Herbert
W.M. PennPublishing Corp., 1952
Buku Teks
edited by Linn C. Stuckenbruck
Addison-Wesley, 1981
Buku Referensi