Wow, that much info has been posted. Concerning this article, I have several notes:
1)The Polish-Lithuanian Commonwealth is traditionally regarded by Russian historians not as a Commonwealth like modern British ("The Commonwealth had given mutual protection to its constituent peoples against the Teutonic Order, the Mongols, the Russians, the Turks, the Swedes and other predatory neighbors until the partitions of the late 18th century"), but like a traditional Middle-Ages Empire led by Polish Kings.
As far as I understand, members of a Commonwealth keep their governments but I don't know anything about such governments on the territories of the Modern Ukraine and Belorussia. So The Rzecz Pospolita (sp?) is an Empire.
There is also an opinion that the Polish oppressed those parts of former Kievan Rus by oppressing Orthodox worshipping as an example.
Taking the above-mentioned Russian attitude into account, the plans of Marshal Pilsudski to include Ukrainian and Belorussian lands look aggressive and imperial, while taking the lands by the Red Army in 1939 look justified.
2)While reading the article one can think that Petliura was a single legitimate Ukrainian leader, what I think to be misleading and inaccurate. He wasn't at all legitimate and wasn't single. There was political chaos in Ukraine at that time and a bunch of self-proclaimed political pretenders: German-supported "Getman" in Kiev, Ukrainian Bolsheviks, Makhno. Marshal Pilsudski allied with Petliura in order to implement his agenda.