Correction to "The output control of linear time-invariant multivariable systems with unmeasurable arbitrary disturbances"

The controller characterization result obtained in the above-named article [ibid., VOI. AC-17. pp. 621-630, Oct. 1972] via equations (64) and (66) is not complete; on applying the same argument as used there, a more general expression is obtained for (66) and presented here.