1. Weissenberg, K., Conference British Rheologist's Club 1946; Proc. 1. Intern. Congr. Rheology, Amsterdam 1948,3, 36 (1949).
2. Oldroyd, J. G., Proc. Roy. Soc.A 200, 523 (1950).
3. Mooney, M., J. Colloid Sci.6, 96 (1951).
4. Truesdell, C., J. Math. pures appl.30, 111 (1951).
5. Philippoff, W., Trans. Soc. Rheol.1, 95 (1957).