1. Venous ulcers of the lower limb;Hannson;Acta Chir Scand,1964
2. Leg and foot ulcers. An epidemiological survey;Anderson;Acta Derm Venereol (Stockh),1984
3. Diseases of the veins-Venous leg ulcers;Ryan,1979
4. Epidemiology of venous thromboembolism;Coon;Ann Surg,1977
5. Nonoperative management of chronic venous insufficiency;Johnson,1991