REFERENCES
- PORTER , WILLIAM A. , 1966 , I.E.E.E. Trans. autom. Control , 11 , 617 .
- RANG , E. E. , 1966 , I.E.E.E. Trans. autom. Control , 11 , 616 .
- SILVERMAN , L. M. , 1966 , I.E.E.E. Trans. autom. Control , 11 , 300 .
- STUBBERUD , A. R. , 1967 , Aerospace Report, TR-1001 (2116-60)-1, April .
- †Communicated by the Authors.