Ahern, Holly
Lowa Wm.C. Brown Pub, 1992
Buku Teks
Northrop, Robert B., author
CRC Press, 2009
Buku Teks
Young, Clarence W., author
Harper & Brothers, 1956
Buku Teks
Eiser, Arthur L., author
Burgess Publishing , 1968
Buku Teks
Setubal, Joao
PWS Publishing Company, 1997
Buku Teks