1. Chaucer, G. 'The Canon Yeoman's Tale' in The Canterbury Tales.
2. Lewis, G. N. J. Am. Chem. Soc. 35, 1448–1455 (1913).
3. http://tagcrowd.com/
4. Liang, C. & Mislow, K. J. Am. Chem. Soc. 116, 11189–11190 (1994).
5. Calladine, C. R., Drew, H. R., Luisi, B. F. & Travers, A. A. Understanding DNA: The Molecule and How It Works 3rd edn (Elsevier, 2004).