::::I still don't see either Burds or Snyder describing these massacres as civil war or even as part of a civil war. They do say there was a civil war but in both cases they seem to be talking about what came after the massacres. 
 ::::This touches upon an issue we have discussed previously and that's the scope of the article. Ideally we would like to have a meta article on the Polish-Ukrainian conflict which could span the interwar period, the occupation period and the immediate post war period and there describing the general events as a civil war would have a place. And then this article would be one of the sub-articles in that conflict. But this article is about massacres in Volhynia and Galicia, which were not a civil war.