M. Consuelo Casabán J. L. Morera G. Rubio Gustavo A. Ossandón The stability of parametricdifference linear systems. 1167-1169 2004 17 Appl. Math. Lett. 10 http://dx.doi.org/10.1016/j.aml.2003.09.010 db/journals/appml/appml17.html#CasabanMRO04