1. H. W. Baxter, Electric Fuses ( Edward Arnold Company, London, 1950 ), pp. 66–76.
2. N. W. McLachlan, Bessel Functions for Engineers (Oxford University Press, New York, 1946 ), pp. 134–135.
3. L. A. Pipes, Applied Mathematics for Engineers and Physicists (McGraw-Hill Book Company, Inc., New York, 1946 ), pp. 366–367.
4. H. S. Carslaw and J. C. Jaeger, Conduction of Heat in Solids (Oxford University Press, New York, 1948), pp. 170–176 and 272–273.
5. J. Crank, The Mathematics of Diffusion ( Oxford University Press, New York, 1956 ), pp. 64–67.