Kwakernaak and Sivan's Linear Optimal Control Systems (1972) was the leading international LQG-control reference for years

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Huibert Kwakernaak co-wrote Linear Optimal Control Systems (Wiley, 1972) with Ravi (bibliographically "Raphael") Sivan of the Technion, written during his early years at the University of Twente. A 2025 obituary by former colleagues describes it as "the leading international reference" on linear-quadratic (LQG) control theory "for many years" — a standard graduate text reconciling classical control with the modern, Kalman-Bucy formulation.

This establishes that the same man whose 1977 paper "Application of Control Theory to Population Policy" fed into Song Jian's one-child-policy mathematics (entity-song-jian) was, independently, the discipline's leading textbook author of the era. The obituary's obituary-writers do not connect these two facts — the population-policy paper and the LQG textbook sit in separate careers in the source itself; the connection is the vault's own synthesis, recorded at observation-kwakernaak-lqg-textbook-bridges-population-policy-and-mccarthy-1973-dismissal.

The Sivan first-name discrepancy ("Ravi" in the obituary text vs. "Raphael" in standard bibliographic citation) is noted but not resolved here; it does not bear on the claim that the book was published and reputationally leading.