Instruct: Classify Amazon reviews into positive or negative sentiment
Query: An objective study

Professor Burgwyn's excellent study of the Italian invasion of Yugoslavia during World War II is likely to be the definitive work on the subject for some time to come. Chronicling Mussolini's invasion requires a great deal of patience and judiciousness, since the cast of characters is large and the main plot breaks down into numerous sub-plots. Moreover, giving an objective account of what happened is not easy, since many observers who write about this murky period have axes to grind. Burgwyn, however, does not base his work mainly on secondary sources. Digging in official archives, he has fashioned a concise and clear narrative out of refractory material. His book, as a leaading historian of the period has said, is an important contribution to the history of World War II.