Special Cases in Using the Matrix Lambert W function for the Stability Analysis of High-Order Linear Systems with Time Delay∗∗This work was supported in part by the Coimbra Group under its program of scholarships for young professors and researchers of Latin America and by the Programme of Interuniversity Attraction Poles of the Belgian Federal Science Policy Office (IAP P6–DYSCO), by OPTEC, the Optimization in Engineering Center of KU Leuven, and by the project G.0712.11N of the Research Foundation-Flanders (FWO).