Bytva dvoch revoljucij perša vijna Ukraïnsʹkoï Narodnoï Respubliky z Radjansʹkoju Rosijeju, 1917-1918 rr = Clash of the two revolutions : the first war between Ukrainian People's Republic and Soviet Russia, 1917-1918 - Kovalʹčuk, Mychajlo Anatolijovyč