Referencias
Mason RJ, Murray J, VC Broaddus, Nadel J. Textbook of Respiratory Medicine. 3rd ed. Philadelphia, Pa: WB Saunders; 2005:1994-2002.
Grainger RC, Allison D, Adam, Dixon AK. Diagnostic Radiology: A Textbook of Medical Imaging. 4th ed. Orlando, Fl: Churchill Livingstone; 2001:339-341; 514-515.