Cinchona - Images of various species, technical description, and distribution. www.nybg.org/bsci/res/CINCHONA.HTML
Cinchona - Source of Quinine - Historical information about the genus and its use, by the late Dr. Fernando Ortiz-Crespo. Includes illustrations. www.cuencanet.com/ortiz/cinchona.htm
Cinchona and its Product - Quinine - Article with a brief description of the genus, its history of use, and cultivation. www.siu.edu/~ebl/leaflets/quinine.htm
Cinchona calisaya - short description and medicinal uses www.botanical.com/botanical/mgmh/c/calisa08.html
Cinchona pubescens - Images, description, and invasiveness. www.hear.org/pier3/cipub.htm
