REFERENCES
- DAVIS , P. F. , 1980 , DN/LC/1018/04028 , Natn. Inst, agric. Engng, Silsoe ( unpublished ) ; 1982, Divisional note, DN/1098, Natn. Inst, agric. Engng, Silsoe (unpublished) .
- JAKEMAN , A. , and YOUNG , P. , 1979 , Int. J. Control , 29 , 621 .
- JAKEMAN , A. J. , YOUNG, P. C, and STEELE , L. P. , 1980 , I.E.E.E. Trans. Syst. Man Cyber , 10 , 593 .
- YOUNG , P. , and JAKEMAN , A. , 1980 , Int. J. Control , 31 , 741 .