August Yulevich Davidov was a Russian mathematician and engineer, professor at Moscow University, and author of works on differential equations with partial derivatives, definite integrals, and the application of probability theory to statistics, and textbooks on elementary mathematics which were repeatedly reprinted from the 1860s to the 1920s. He was president of the Moscow Mathematical Society from 1866 to 1885.
August Davidov
Title page of Davidov's textbook Geometry
Nikolay Zhukovsky (scientist)
Nikolay Yegorovich Zhukovsky was a Russian scientist, mathematician and engineer, and a founding father of modern aero- and hydrodynamics. Whereas contemporary scientists scoffed at the idea of human flight, Zhukovsky was the first to undertake the study of airflow. He is often called the Father of Russian Aviation.
Nikolay Zhukovsky (scientist)
Collected paper Nikolay Zhukovsky. Theoretical basis aeronautics.
Stamp from the USSR Aviation series 1963 dedicated to Zhukovsky (CFA 2915, Scott 2774)
1947 stamp