Meyer, Evelyn E.
World Health Organization, 1975
Buku Teks
Treshow, Michael
McGraw-Hill, 1976
Buku Teks
edited by Jonathan Rigg
Archipelago Press, 1996
Buku Teks
Knapp, Brian
Longman House, 1992
Buku Teks
Walter, Eugene Victor
Chapel Hill, 1988
Buku Teks