Web-based references relating to the number under the disk sign 
1 Image of mad-hatter--wearing three hats, courtesy of OUP; no link available; page iv
2 Jeanne Lenzer 2008. Doctor takes 'march of shame, to atone for drug company payments. BMJ 2008 336 20. [Link]; page v
3 Image of abbreviations courtesy of JM Longmore; no link available; page xi
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