“…The model reduction problem has aroused a continual interest in the engineering community since the dawn of control and system theory [40,71], its importance being evident not only in system simulation and controller synthesis but also in many problems related to robustness and uncertainty issues. Indeed, despite the dramatic increase of computing capabilities that make the need for simplified models less compelling, the new challenges facing the control engineer have led to a revival of studies on this topic with particular emphasis on optimisation and algorithmic efficiency (see, e. g., [1,2,4,7,11,12], [14]- [59], [61,65,69,70]).…”