1. Anderson AW (1847) Hair extracted from ulcer. Boston Med Surg 36:74
2. Bascom R (1980) Pilonidal disease: Origin from follicles of hairs. Surgery (St Louis) 87:567
3. Brearly R (1955) Pilonidal sinus -a new theory. Br J Surg 43:62
4. Carstensen E, Keichel F (1963) Ätiologie und Therapie des Pilonidalsinus. Chirurg 34:303
5. Davage ON (1954) Pilonidal sinus. Am J Pathol 30:1191