. . . . . . . . "\u0098The \u009Cmathematical theory of optimal processes / by L. S. Pontryagin, V. G. Boltyanskii, R. V. Gamkrelidze... [et al] ; translator K. N. Trirogoff ; editor L. W. Neustadt / New York : Interscience publishers, a division of John Wiley & sons" . . . "44"^^ . . .