REFERENCES
- CHANG , J. , 1961 , Autn remote Control , 22 , 1463 .
- KALMAN , R. E. , 1964 , J. bas. Engng , 86 , 51 .
- KLIGEK , I. , 1964 , I.E.E.E. Trans, autom. Control , 58 .
- LEITMANN , G. , 1966 , An Introduction to Optimal Control ( New York McGraw-Hill ).
- REKASIUS , Z. V. , and HSIA , T. C. , 1964 , I.E.E.E. Trans, autom. Control , 37 .
- ROHRBII , R. A. , and SOBRAL , M. , 1966 , J. bas. Engng , 88 , 323 .
- SACK , A. P. , 1968 , Optimum Systems Control ( Englewood Cliffs , N.J., Prentice-Hall, Inc. ).
- SUUSENA , H. R. , 1968 , Int. J. Control , 8 , 65 .
- WONHAM , W. M. , and JOHNSON , C. D. , 1964 , J. bas. Engng , 86 , 107 .
- †Communicated by the Authors