1. Angell, T.S.: On controllability for nonlinear hereditary systems: a fixed-point approach, Nonlinear Anal., 4 (1980), pp. 529–545.
2. Bohnenblust, H.F., and Karlin, S.: On a theorem of Ville Contributions to the theory of games I, Annals of Mathematics Studies No. 24, Princeton Univ. Press, 1950, pp. 155–160.
3. Carmichael, N., Pritchard, A.J., and Quinn, M.D.: Nonlinear control and estimation in "Evolution equations and their applications, F. Kappel and W. Schappacher, Eds., Pitman 1982, pp. 30–51.
4. Carmichael, N., Pritchard, A.J., and Quinn, M.D.: State and parameter estimation for nonlinear systems, Appl. Math. & Opt., 9 (1982), pp. 133–161.
5. Carmichael, N., and Quinn, M.D.: Some ill-posed problems in control theory, Oberwolfach conference on ill-posed problems and regularisation techniques, September 1982.