Guttiferae
- Botanical characteristics of this family, sometimes classified as Clusiaceae, with drawings of a number of species.
- http://delta-intkey.com/angio/www/guttifer.htm

Clusiaceae
- The characteristics of the St John’s Wort family, formerly Guttiferae, which includes about 1000 species.
- http://www.theseedsite.co.uk/clusiaceae.html

The Clusiaceae
- Information on this family with photographs of a number of species.
- http://www.botany.hawaii.edu/faculty/carr/clusi.htm