The Maple worksheet for the computation of the first two focal values for the paper

(with B. Boros, J. Hofbauer, S. Müller) Planar S-systems: Global stability and the center problem, Discrete and Continuous Dynamical Systems 39 (2019) pp. 707-727 DOI | arXiv

is available here and as a PDF here.

A fact sheet on planar S-systems maintained by Balázs Boros is available here.