Collection contains scrapbooks, newspaper clippings, letters, personal papers, membership cards, sketches, ephemera, fliers, programs, scores, photographs, and other materials relating to Ennio Bolognini's musical career, 1847-1979.

This series contains documents relating to the Belgian Piano-String Quartet: manuscript history of the first decade, repertory lists, concert programs (1933-1941), manuscript biographical notes on various composers with ties to Wetzels or those Wetzels had interest in, and photographs of the Quartet (autographed), 1928-1942.

The Joseph Wetzels scores and papers consists predominantly of music scores, namely for piano-string quartet used by the Belgian Piano-String Quartet, string quintet, piano-string trio, string quartet, and folk songs in the form of printed score, manuscript parts, or photocopies. The collection also contains documents relating to the Belgian Piano-String Quartet in the form of repertory lists, concert programs, and photographs, 1918-1942.