MR0312936 Yosida, Setuz{\^o} Setuzô YOSIDA Funkcialaj Ekvacioj. Serio Internacia 14 1971 61--71 http://fe.math.kobe-u.ac.jp/FE/Free/vol14/fe14-5.pdf http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE11-20-en_KML/fe14-061-071/fe14-061-071.pdf http://www.ams.org/mathscinet-getitem?mr=MR0312936 fe14-061-071 1971 YOSIDA, Setuz\^o YOSIDA, Setuz\^o 1 Lee, E. B.; Markus, L. Foundations of Optimal Control Theory Wiley, New York 1967 MR0220537 100 Cache/Le/Lee,Foundations,*,1967,1968 x+576 2 Lefschetz, S. Differential Equations: Geometric Theory, 2nd ed. Interscience, New York 1963 MR0153903 100 Cache/Le/Lefschetz,*,*,1963,1964 x+390 3 Pontryagin, L. S.; Boltyanski, V. G.; Gamkrelidze, R. W.; Mishchenko, E. F. The Mathematical Theory of Optimal Processes Sogotosyo, Tokyo 1967 (Japanese translation from Russian original) MR0186436 Cache/Po/Pontryagin,Mathematical,*,1967,1968