1. Donzelot, E., Heim de Balsac, R. (1947). Arch. Mal. Coeur., 40, 462.
2. Goodwin, J. F., Steiner, R. E., Lowe, K. G. (1952). J. Fac. Radiol., 4, 21.
3. Gough, J., Wentworth, J. E. (1949). J. Fac. Radiol., 1, 28.
4. A Textbook of X-ray Diagnosis by British Authors;Kerley, P.,1951
5. Laubry, C., Chaperon, R., Sejourn6 (1929). Presse me'd., 37, 1653.