1. V. F. Berdikov, A. V. Babanin, and Yu. N. Artem'eva, ?Determination of the Young's moduli of various abrasive materials by the microindentation method,? Zavod. Lab., No. 8, 1014?1019 (1975).
2. T. R. Wilshaw, ?The Hertzian fracture test,? J. Phys. D, Appl. Phys.4, No. 2, 1561?1581 (1971).
3. A. G. Evans and T. R. Wilshaw, ?Quasistatic solid particle damage in brittle solids. I. Observation, analysis and implications,? Acta Metall.,24, No. 3, 939?956 (1976).
4. A. G. Evans and E. A. Charles, ?Fracture toughness determinations by indentations,? J. Am. Ceram. Soc.,59, No. 7/8, 371?372 (1977).
5. I. Ya. Shtaerman, Contact Problem of the Theory of Elasticity [in Russian], Gostekhteorizdat, Moscow-Leningrad (1949).