1. Allen, R L M, Colour Chemistry, 1971, Nelson, Great Britain.
2. Christie, R M, Colour Chemistry, 2001, Royal Society of Chemistry, Cambridge.
3. A History of Dyes. http://www.straw.com/sigdyehist.html
4. The Woad Page. http://my.net-link.net/~rowan/crafts/woad/woadpage.html
5. Chemistry of natural and synthetic indigo dyes. http://chriscooksey.demon.co.uk
6. From caveman to chemist. http://cator.hsc.edu/~kmd/caveman/projects/dye/index.html
7. Clothing of the Ancient Celts- Dyeing. http://www74.pair.com/lindo/dyes.htm
8. Cochineal. http://www.botgard.ucla.edu/html/botanytextbooks/economicbotany/Cochineal/
9. The pigments page. http://webexhibits.org/pigments/indiv/overview/alizarin.html
10. Etherington and Roberts Dictionary. http://palimpsest.stanford.edu/don/don.html
11. The Textile Artists Newsletter. http://www.straw.com/tan/tan_fiberreactives.html
12. Logwood and Brazilwood. http://waynesword.palomar.edu/ecoph4.htm
13. Encyclopaedia Britania.