^ 1.01.1Gupta, R.S. Khurmi, J.K. A textbook of machine design (S.I. units) : [a textbook for the students of B.E. / B.Tech., U.P.S.C. (Engg. Services); Section 'B' of A.M.I.E. (1)] 14th. Ram Nagar, New Delhi: Eurasia Publishing House. 2008. ISBN 81-219-2537-1.