1. Shakespeare W. Henry IV, act III, scene 11, line 71.
2. Cooper P. The craft of surgery. Boston: Little, Brown, 1964:1259.
3. Corman ML. Colon and rectal surgery. Philadelphia: JB Lippincott, 1984:56–7.
4. Goligher JC. Surgery of the anus, rectum, and colon. London: Bailliere Tindall, 1984:143–4.
5. Jackman RJ. The management of hemorrhoidal thrombosis. GP 1956;:82–3.