1. Kumar V, Abbas AK, Aster J, .Robbin and Cottran Pathologic Basis of Disease.
2. Mohan H, .Textbook of Pathology .
3. Park K, .Park's textbook of Preventive and Social Medicine.395
4. Suryakanta AH, .Community Medicine.529
5. Longo DL, Kasper DL, Jameson JL, Fauci AS, Hauser SL, Loscalzo J, Disorders of Cardiovascular system.Harrison's Principles of Internal Medicine 2011;Vol 1:243