1. Toms, B. A., Proc. First Intern. Cong. on Rheology, 2, 135 (North-Holland Publishing Company, 1948).
2. Foreman, jun., J. W., George, E. W., Felton, J. L., Lewis, R. D., Thornton, J. R., and Watson, H. J., J. Inst. Elect. Electron Eng., QE-2, 260 (1966).
3. Goldstein, R. J., and Kreid, D. K., J. Appl. Mech., 34, 813 (1967).
4. Rudd, M. J., J. Sci. Instrum., 2, 55 (1969).
5. Welch, N. E., and Tomme, N. J., Fifth Aerospace Sciences Meet. (1967).