The Maple worksheet for the computation of the first two focal values for the paper
(with B. Boros, J. Hofbauer, S. Müller) The center problem for the Lotka reactions with generalized mass-action kinetics, Qualitative Theory of Dynamical Systems, 8 pages, 2017. DOI | arXiv
is available here and as a PDF here.
A CDF file (created with Mathematica) containing 3-dimensional visualizations of the center variety is available here.