Grigyaleis, A. On the conditional extremum in problems with free boundary. (Russian. English summary) Zbl 0621.49001 Differ. Uravn. Primen. 38, 15-22 (1986). MSC: 49J20 35R35 93C20 PDFBibTeX XMLCite \textit{A. Grigyaleis}, Differ. Uravn. Primen. 38, 15--22 (1986; Zbl 0621.49001)
Kibenko, Anatolij; Gusar, Viktor On the problem of optimal stabilization for nonlinear systems. (Russian. English summary) Zbl 0573.49001 Differ. Uravn. Primen. 32, 46-56 (1982). MSC: 49J15 93C10 93D15 49M99 93C15 PDFBibTeX XMLCite \textit{A. Kibenko} and \textit{V. Gusar}, Differ. Uravn. Primen. 32, 46--56 (1982; Zbl 0573.49001)
Kambulov, Viktor; Sirsikov, Eugeni The controllable autogenerator with the hybrid RC-structure in the chain of feedback. (Russian) Zbl 0398.93026 Differ. Uravn. Primen. 20, 9-15 (1978). MSC: 93C20 93D99 PDFBibTeX XMLCite \textit{V. Kambulov} and \textit{E. Sirsikov}, Differ. Uravn. Primen. 20, 9--15 (1978; Zbl 0398.93026)