Digital computer applications to process control : proceedings of the 6th IFAC/IFIC Conference, Dusseldorf, F R Germany 14-17 October, 1980/ by Isermann, Rolf, Kaltenecker, H., International Federation of Automatic Control. Technical Committee on Applications, International Federation for Information Processing, IFAC/IFIP Conference (6th : 1980 : Dusserdorf, F R Germany)