1. B.M. Pevzner, Pumps of Marine Installations and Systems (Sudostroenie, Leningrad, 1971) [in Russian].
2. D. F. Baldenko, M. G. Bidman, V. L. Kalishevskii, et al., Screw Pumps (Mashinostroenie, Moscow, 1982) [in Russian].
3. S. G. Valyukhov, V. A. Kostin, Yu. I. Sapronov, and S. M. Semenov, Optimization of Gear Screw Surfaces (Voronezhsk. Gos. Univ., Voronezh, 2005) [in Russian].
4. V. I. Arnold, A. N. Varchenko, and S. M. Gusein-Zade, Singularities of Differentiable Maps. Classification of Critical Points, Caustics, and Wave Fronts (Nauka, Moscow, 1982) [in Russian].
5. J. W. Bruce and P. G. Giblin, Curves and Singularities. A Geometrical Introduction to Singularity Theory (Cambridge University Press, 1984; Mir, Moscow, 1988).