SIAM Journal on Control and Optimization vol. 37 n. 5 (1999) AUTHOR TITLE PAGE Jay S. Treiman Lagrange Multipliers for Nonconvex 1313 Generalized Gradients with Equality, Inequality, and Set Constraints M. A. Peters, A Spectral Test for Observability and 1330 P. A. Iglesias Reachability of Time-Varying Systems Matthew Kiefer, Parametrized Families of Extremals and 1346 Heinz Schättler Singularities in Solutions to the Hamilton--Jacobi--Bellman Equation Jordan M. Berg, On Parameter Estimation Using Level Sets 1372 Kenneth Holmström George Avalos, Lack of Time-Delay Robustness for 1394 Irena Lasiecka, Stabilization of a Structural Richard Rebarber Acoustics Model Birgit Jacob, Equivalent Conditions for Stabilizability 1419 Hans Zwart of Infinite-Dimensional Systems with Admissible Control Operators Jean-Claude Fort, Asymptotic Behavior of a Markovian 1456 Gilles Pagès Stochastic Algorithm with Constant Step François Dufour, Stability of Piecewise-Deterministic 1483 Oswaldo L. V. Costa Markov Processes Andrzej Banaszuk, A Backstepping Controller for a Nonlinear 1503 Höskuldur Ari Hauksson, Partial Differential Equation Model of Igor Mezic Compression System Instabilities Mariateresa Napoli, Two-Dimensional Proper Rational Matrices 1538 Sandro Zampieri and Causal Input/OutputRepresentations of Two-Dimensional Behavioral Systems A. Brockwell, Stability of an Adaptive Regulator for 1553 K. Borovkov, Partially Known Nonlinear Stochastic R. Evans Systems Peng-Fei Yao On The Observability Inequalities for 1568 Exact Controllability of Wave Equations With Variable Coefficients Tzanko Donchev, Averaging Method for One-Sided Lipschitz 1600 Iordan Slavov differential inclusions with Generalized Solutions Mingqing Xiao, Finite-Dimensional Compensators for the 1614 Tamer Basar H-infty-Optimal Control of Infinite- Dimensional Systems via a Galerkin-type Approximation