1. Smithsonian Physical Tables, ninth ed. (1954).
2. Tolansky, S., Multiple Beam Interferometry (Clarendon Press, Oxford, 1948).
3. Tolansky, S., Surface Microtopography (Longmans, 1960).
4. Scott, G. D., McLauchlan, T. A., and Sennett, R. S., J. App. Phys., 21, 843 (1950).
5. Donaldson, W. K., and Khamsavi, A., Nature, 159, 228 (1947).