Kelley's 1960 "Gradient Theory of Optimal Flight Paths" cites no work by Nyquist, Bode, or classical control theory

control-theorynyquistbodeoptimal-controlkelleybackpropagation-originshistory-of-technologycalculus-of-variations

Henry Kelley's "Gradient Theory of Optimal Flight Paths" (ARS Journal 30, October 1960, pp. 947–954) — credited elsewhere in the vault as the earliest node of the Kelley/Bryson optimal-control-to-backpropagation precursor lineage (claim-kelley-bryson-optimal-control-precursor) — carries a 29-entry numbered reference list. Read in full at capture time, every entry is either mathematics of the calculus of variations and gradient/numerical methods (Hestenes, Hadamard, Courant, Bliss, Curry, Stein, Hestenes & Stiefel, Forsythe & Forsythe, Muller, Friedman, Goodman & Lance, Courant & Hilbert, Tompkins) or contemporary rocket/flight-path and solar-sail trajectory work (Garfinkel, Cicala, Miele, Breakwell, Okhotsimskii & Eneev, Leitmann, Mengel, Irving & Blum, Faulders, Garwin, Cotter, Tsu, London, Kelley's own 1958 thesis). The first reference — the earliest work Kelley cites, and the one his method most directly extends — is Magnus Hestenes's "A General Problem in the Calculus of Variations with Applications to Paths of Least Time," RAND RM-100, March 1950. No reference to Harry Nyquist, Hendrik Bode, "regeneration theory," "feedback amplifier," or "classical control theory" appears anywhere in the paper's text or bibliography.

This closes the cheapest of the checks named by claim-nyquist-bode-classical-control-to-optimal-control-bridge's own commentary and by question-verify-nyquist-bode-optimal-control-transmission-line: Kelley's own stated lineage, in his own words, is the RAND/calculus-of- variations rocket-trajectory tradition, not Bell Labs stability theory. It is a documented absence in one node of the four-name chain the open question named (Kelley) — not a claim about Pontryagin's, Bellman's, or Bryson's own citation practices. Bryson's 1961 paper remains unread anywhere in the vault, a gap already noted in claim-kelley-bryson-optimal-control-precursor and in claim-recht-adjoints-equivalence-not-transmission, which reports being unable to locate the 1961 proceedings at all.