1. Abbott, J. A., Whipple, G. H.: Paradoxic splitting of the second heart sound in systemic hypertension. The role of myocardial competence. Dis. Chest 46, 304 (1964).
2. Abrams, J.: Essentials of cardiac physical diagnosis, p. 6. Philadelphia: Lea & Febiger 1987.
3. Adolph, R.J., Fowler, N. O.: The second heart sound: A screening test for heart disease. Mod. Cone, cardiov. Dis. 39, 91 (1970).
4. Allen, N.: The significance of vascular murmurs in the head and neck. Geriatrics 20, 525 (1965).
5. Allen, H., Harris, A., Leatham, A.: Significance and prognosis of an isolated late systolic murmur: A 9-to-22 year fol- low-up. Brit. Heart J. 36, 525 (1974).