1. Wellman, H. W., and Wilson, A. T., Nature, 205, 1097 (1965).
2. Brückner, W. D., and Anderson, M. M., Quaternaria, 5, 95 (1962).
3. King, L. C., The Morphology of the Earth (Oliver and Boyd, 1962).
4. See, for example, Holmes, A., Principles of Physical Geology (Nelson, 1965); Louis, H., Allgemeine Geomorphologie (Walter de Gruyter and Co., Berlin, 1961); Longwell, C. R., Knopf, A., and Flint, R. F., Physical Geology (John Wiley and Sons, 1948); and other authors discussing this controversial topic of physical weathering.
5. Twidale, C. R., Zeitschr.f. Geomorphologie, N. F., 6, 51 (1962).