1. Bowden, F. P., and Ridler, K. E. W., Proc. Roy. Soc., A, 151, 610 (1936).
2. Beams, J. W., J. Washington Acad. Sci., 37, 221 (1947).
3. Reynolds, O., “Paper on Mechanical and Physical Subjects, 2” (Cambridge University Press, 1901).
4. Bowden, F. P., and Hughes, T. P., Proc. Roy. Soc., A, 172, 280 (1939).
5. Bowden, F. P., Proc. Roy. Soc., A, 217, 462 (1953). See also Hawksley Lecture, J. Inst. Mech. Eng., 2, 86 (1955).