↑ Maton, Anthea (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN0-13-981176-1. Unknown parameter |coauthors= ignored (|author= suggested) (help)
↑ Guyton, Arthur C.; Hall, John E. (2006). Textbook of Medical Physiology. Philadelphia: Elsevier Saunders. p. 310. ISBN0-7216-0240-1.CS1 maint: Multiple names: authors list (link)
