1. Wang KP, Mehta AC, Turner JF (eds.). Flexible Bronchoscopy. 2nd Edition. Blackwell Publishing, 2004.
2. Fraser RS, Muller NL, Colman N, Pare PD (eds.). Diagnosis of Diseases of the Chest. 4th Edition. W.B. Saunders Company, 1999.
3. Pearson GF, Cooper JD, Deslauriers J, et al. (eds.). Thoracic Surgery. Second Edition. Churchill Livingstone, 2002.
4. Griscom NT, Wohl ME. Dimensions of the growing trachea related to Age and Gender. AJR Am J Roentgenol 1986; 146(2): 233–237.
5. Cleveland RH. Symmetry of bronchial Angles in Children. Radiology 1979; 133(1): 89–93.