World Health Organization, 1991
Buku Referensi
Garoutte, Michael P., author
John Wiley & Sons, Inc, 2007
Buku Teks
Mishustin, E.N.
The Pennsylvania State University Press, 1971
Buku Teks
Roberts, E.A
Chapman & Hall, 1992
Buku Teks
edited by Michael J. Brennan, and William L. Simpson
Little, Brown, 1962
Buku Teks