References
- BHAITA , N. P. , and SZBOO , G. P. , 1967 , Dynamical Systems Stability Theory and Applica¬tions ( Berlin Springer Verlag ).
- BIIIKHOFF , G. D. , 1927 , Dynamical Systems ( New York American Mathematical Society ), Chapter 7 .
- LEFSCHETZ , S. , 1903 , Differential Equations Geometric Theory ( New York Interscience ), Chapter 2 .
- LiAruNOV , A.M. , 1949 , Probleme general de la Stabiliti du Mouvement ( Princeton Princeton University Press ).
- RHOTEN , R. P. , and MULHOLLAND , R. J. , 1971 , Int. J. Control ( in press ).
- SIMS , C. S. , RHOTEN , R. P. , and MULHOLLAND , R. J. , 1972 , Int. J. Control , ( in press ).
- †Communicated by the Author. Supported in part by N.S.F. Departmental Science Grant GTJ-3160 and N.S.F. Research Grant GK-5283.