Variable stepsize continuous two-step Runge-Kutta methods for ordinary differential equations. - Zdzislaw Jackiewicz; S. Tracogna (Numer. Algorithms, 1996)

About the sharpness of the stability estimates in the Kreiss matrix theorem. - Marc Nico Spijker; S. Tracogna; Bruno D. Welfert (Math. Comput., 2003)