1. A.S. Morse: "Recent Problems in Parameter Adaptive Control", pp. 733–740, Vol. 3, Outils et Modèles Mathématiques pour l'Automatique, l'Analyse de Systèmes et le Traitement du Signal, Ed. I.D. Landau, Editions du CNRS, 1983.
2. R.D. Nussbaum: "Some Remarks on a Conjecture in Parameter Adaptive Control", Systems and Control Letters, Vol. 3, No. 5, pp. 243–246, 1983.
3. A.S. Morse: "An Adaptive Control for Globally Stabilizing Linear Systems with Unknown High-Frequency Gains", Department of Electrical Engineering, Yale Univ., Report No. 8402, January 1984.