1. Allen, D. S.: Arch. franco-belg. Chir.28, 394 (1925).
2. Adams-Ray, J.:St. Hagberg u.P. Hjelmström: Acta chir. scand. (Stockh.)109, 261 (1955).
3. Bailey, C. P.: Diss. Chest.15, 377 (1949).
4. : Surgery of the Heart. Philadelphia: Lea a. Febiger 1955.
5. Bailey, C. P., H. E. Bolton, W. L. Jamison andH. B. Larzelere: J. Int. Coll. Surg.20, 393 (1953).