1. Tschoegl, N. W. (to be published in this journal).
2. Widder, D. F., The Laplace Transform (Princeton, N.J. 1946).
3. Smith, T. L. (to be published in J. Polymer Sci. C).
4. Hirschman, I. I. and D. V. Widder, The Convolution Transform, p. 70 (Princeton, N.J. 1955).
5. Widder, D. F., The Laplace Transform (Princeton, N.J. 1946). Ref. 2, pp. 345 and 350.