1. Indian Standard Methods of Sampling and Testing of Refractories Materials, p. 9, IS: 485 (1953).
2. Andrews, A. I.Ceramic Tests and Calculations, pp. 107–110, John Wiley and Sons, London (1945).
3. Grim, R. E.Clay Mineralogy, p. 193, McGraw-Hill Book Company, New York (1953).