The Battle Hymn of the Republic by 
Crisis music: the cultural politics of rock against racism by Start with a keyword search and identify some relevant books. Then look at the subject headings for those books. You can follow the subject heading links in the catalog to find similar books, or you can use the terms in the subject headings to identify other keywords to try.
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Protest songs -- 20th century -- History and criticism
Musicians -- Political activity
Popular music -- Political aspects
Social movements -- History -- 20th century
Story behind the protest song: a reference guide to the 50 songs that changed the 20th century by 
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