Tyrell, L.W.M.
ELBS, 1971
Buku Teks
Rasanayagam, L.J., author
Federal Publications, 1991
Buku Teks
Leicester, Henry M.
McGraw-Hill, 1952
Buku Teks
Sienko, Michell J., author
McGraw-Hill Kogakusha, 1961
Buku Teks
Busch, Daryle H., author
Allyn and Bacon , 1978
Buku Teks