Positive Decomposition of Transfer Functions with Multiple Poles. - Béla Nagy; Máté Matolcsi; Márta Szilvási (POSTA, 2006)

Order Bound for the Realization of a Combination of Positive Filters. - Béla Nagy; Máté Matolcsi; Márta Szilvási (IEEE Trans. Autom. Control., 2007)