1. S. Tolansky, ?Multiple Beam Interferometry? (Oxford University Press, Oxford, 1947).
2. S. Tolansky, Z. Electrochem. 56 (1952) 263.
3. A. H. Bannet, H. Osterberg, H. Jupnik and O. W. Richards, ?Phase Microscopy? (John Wiley and Co. Inc., New York).
4. R. A. Daly, Proc. Amer. Acad. Arts Sci. 34 (1899) 373.
5. A. P. Honess, ?Nature, Origin and Interpretation of Etch Figures on Crystals? (John Wiley, New York, 1927).