1. Bedford, D. E. (1939). Lancet, 1, 1303.
2. Bedford, D. E., and Lovibond, J. L. (1941). Brit. Heart J., 3, 93.
3. Donzelot, E., and Heim de Balsac, H. (1947). Arch. Mal. Cwur, 47, 1.
4. Cardioscopy;Evans, W.,1952
5. A Treatise on the Diseases of the Heart and Great Vessels;Hope, J.,1839