Under Rudolf Barth, a set of Geistliche Volkslieder für Sopran, Alt, Tenor und Bass was published by Bertelsmann in 1893. Danish Library in their entry for his opus 10 (Mädchen träumereien) has fl.1835, though (this was published, like op.11, around 1865 or so (HMB Sept.-Oct. 1865) - Worldcat gives 1910 - according to HMB and Hofmeisters Handbuch der Musikliteratur, which also lists a D minor opus 2 violin sonata by "R. Barth" from 1869 which may be by Richard Barth (except that his opus 2, Deutsche Walzer für das Pf zu vier Händen., was published in 1873. Hrm.) HMB also has a "Suite Op.5 in D" for piano by "Rudolf" Barth published in 1911...
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