Expo du Jardin des Plantes 1997

http://www.mnhn.fr/expo/pelargonium

Geraniums (genus Pelargonium)

http://www.ianr.unl.edu/pubs/Horticulture/g190.htm

Geranium Culture for Home Gardeners

http://www.ces.ncsu.edu/hil/hil-8504.html