1. Lectures on the theory of approximation.;Akhiyezer,1947
2. Concerning approximate solution of non-linear functional equations;Altman;Bull. Acad, polon. Sei.,1957
3. The theory of optimum processes;Boltanski;DAN SSSR,1956
4. Analysis and design considerations of second and higher order contactor saturating servomechanisms;Kalman;Trans. Amer. Inst, elect. Engrs,1955
5. One problem of optimum control;Krasovski;Automat. Telemech., Moscow,1957