Ambrosia artemisiifolia
- Illustration, systematic position, morphology, biology, distribution, ecology and economic significance of Common Ragweed.
- http://www.agroatlas.spb.ru/weeds/Ambrosia_artemisiifolia_en.htm

A Close-up View of Common and Great Ragweed
- Photographic study by Brian Johnston of Ambrosia artemisiifolia and Ambrosia trifida, with fine images of flowers, stems, leaves and fruits.
- http://www.microscopy-uk.org.uk/mag/artoct04/bjambro.html

Ambrosia trifida
- Great Ragweed.
- http://plants.usda.gov/java/profile?symbol=AMTR