<human>:  What books would you recommend on learning about the history of the Polish-Ukrainian conflict?
<bot>: I would recommend "The Polish-Ukrainian Conflict: A Historical Outline" by Halina Niec, "An Outline of the Ukrainian-Polish Conflict in the 20th Century" by Taras Tyshchenko, and "The root causes of the Ukrainian-Polish Conflict: Historical Perspectives" by Jan Sobiesiak.