1. 1. Loeb Classical Library: Hippocrates. Diseases II. 1988; 5: 61: 306-307. Ref.: https://goo.gl/dHinsJ
2. 2. Hajar R. The art of listening. Heart Views. 2012; 13: 24-25. Ref.: https://goo.gl/h6uVrp
3. 3. Gotfredsen E. The History of Medicine. Copenhagen: New Nordic Publisher Arnold Busck. 1964.
4. 4. Walker HK, Hall WD, Hurst JW, ed. Clinical Methods: The history, physical and laboratory examinations. 3rd edition. Boston: Butterworths, 1990; Chapter 1. Ref.: https://goo.gl/8BiYMh
5. 5. Bastholm E. Laennec and the stethoscope. Danish Medical History Yearbook. 1982; 112-35