[Retros] Programs for Solving Retro Problems

[marko at ffri.hr]

Dear colleagues,

On janko.at web site, under subject "Programs for Solving Retro Problems",
these five programs are given: Euclide, Retractor, Popeye, Natch and
iNatch.
I'm interesting are these programs the best (most seriously) what exist?

Thank you very much for your replay and greetings from Croatia,

Marko Malikovic
Faculty of Arts and sciences
Rijeka, CROATIA