1. Graphical Analysis of Control Systems
2. Quadratic weights for asymptotic regulator properties
3. JOHNSON , M. A. , and GRIMBLE , M. J. , 1979 , Sheffield City Polytechnic Reports EEE/39/1979 and EEE/40/1979, (Revised EEE/58/1980, EEE/67/1980; 1980 a, Sheffield City Polytechnic Report EEE/52/1980 ; 1980 b, Sheffield City Polytechnic Report EEE/69/1980; 1980 c, Sheffield City Polytechnic Report EEE/68/1980.
4. KOUVARITAKIS , B. , 1978 ,Int. J. Control, 27 , 705 .