1. Mason P. Napoleon’s haemorrhoids: and other small events that changed history. Philadelphia: Skyhorse Publishing; 2009.
2. Milligan ETC, Morgan CN, Jones LE, et al. Surgical anatomy of the anal canal and the operative treatment of haemorrhoids. Lancet. 1937;2:1120–4.
3. Thomson WHF. The anatomy and nature of piles. In: Kaufman HD, editor. The haemorrhoid syndrome. Tunbridge Wells: Abacus; 1981. p. 15–33.
4. Johnson FP. The development of the rectum in human embryo. Am J Anat. 1914;16:1–57.
5. Lestar B, Pennickx F, Rigauts H, et al. The internal sphincter cannot close the anal canal completely. Int J Colorectal Dis. 1992;7(3):159–61.