Symmetry analysis of Control Systems.

• Lehenkyi V. The Integrability of Some Underdetermined Systems // Proceedings of Institute of Mathematics of NAS of Ukraine 2000, Vol. 30, Part 1, 157–164.
• Lehenkyi V., Rudolph J. On a characteristic vector field for systems reducible to order two, in: Prepr. "16th IFAC World Congress, Prague, Czech Republic, July 3–8, 2005", CDROM (6 pages).

• Institute of Mathematical Machines and Systems Problems of the Ukraine National Academy of Science