Comments on "Linear quadratic regulators with eigenvalue placement in a vertical strip"

In the original paper by Shieh, Hani and McInnis (ibid., vol.31, p.241-3, 1986), a method was proposed for the design of linear feedback control such that all the poles of the closed-loop system lie in a vertical strip. There are errors in the conditions for the eigenvalues to lie in the open vertical strip and also in the proof of a theorem. We correct these inaccuracies.