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For general criticism on an author, look for "criticism and interpretation" after the author's name (e.g. Fontane, Theodor, 1819-1898 -- Criticism and interpretation)
For criticism of a particular work, look for the title after the author's name (e.g. Fontane, Theodor, 1819-1898. Effi Briest).
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The chapter "Revolution, Resignation, Realism (1830–1890)" by Gail Finney will be particularly useful.
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