1. K. K. Papok and E. G. Seminido, Motor and Jet-Engine Lubricants and Fluids [in Russian], Khimiya, Moscow (1963), p. 123.
2. C. M. Larson, Petrol. Engr.,27, No. 3, 44?53 (1955).
3. R. S. Aries and A. P. Sachs, Petrol. Refiner, No. 5, 236 (1956).
4. E. Koch, Erdoel Kohle, No. 11, 793?796 (1955).
5. T. Salomon, Rev. Inst. Franc. Petrole,11, No. 4 (1956).