1. U. S. Pat. 3,219,666, 3,272,746 (1966);
2. E. Forbes, Neustadter, Tribology, p. 72 (1972).
3. V. I. Isagulyants, A. P. Polyakov, and I. P. Leonova, Khim. Tekhnol. Topl. Masel, No. 12, 21 (1970).
4. A. P. Polyakov, V. I. Isagulyants, and N. M. Merzlyakova, Khim. Tekhnol. Topl. Masel, No. 7, 16 (1973).
5. V. G. Ostroverkhov, O. L. Glavati, and E. P. Fursa, Khim. Tekhnol. Topl. Masel, No. 2, 16 (1976).