1. 1. Mulley AG, Goroll AH. Primary Care Medicine. 4th ed. Lippincott Williams and Wilkins Publishers; 2000, Chapter 31, p. 22.
2. 2. Humphreys M. Nursing the Cardiac Patient. 1st ed. Britain: Blackwell; 2011, Chapter 9, pp. 113–126.
3. 3. Brown DL. Cardiac Intensive Care, 2nd ed. Philadelphia: Elsevier Inc. editor; 2010. p. 81, p. 73.
4. 4. Levine GN. Cardiology Secrets. 3rd ed. Philadelphia: Mosby Inc; 2010. Chapter 21, pp. 143–145.
5. 5. Sidebotham D. Cardiothoracic. Crit Care. 1st ed. 2007. Chapter 9, p. 148.