Wilk, Andrzej. The Best Army Ukraine Has Ever Had: Changes in Ukraine?s Armed Forces since the Russian Aggression. OSW, Centre for Eastern Studies, 2017.

Olsza?ski, Tadeusz A., Jan Strzelecki, and Andrzej Wilk. "Kyiv refuses to make concessions to the separatist republics?" Center for Eastern Studies (OSW), Analyses (2015).