Musicologist and collector Hans Moldenhauer's extensive collection of primary sources, documenting medieval chant through serialism, is today distributed among nine institutions throughout the world: in the United States, the Library of Congress, Harvard University, Northwestern University, Washington State University, and Whitworth College; in Basel, the Paul Sacher Stiftung; in Munich, the Bayerische Staatsbibliothek; in Zurich, the Zentralbibliothek; and in Vienna, the Stadtarchiv und Oesterreichische Nationalbibliothek.
Northwestern's holdings of the Moldenhauer Archives are recorded in the Music Library's manuscripts card catalog. Researchers may examine microfilm copies of Moldenhauer items held by Northwestern; access to the original documents is provided only under special circumstances.
Fuller descriptions of the items are available in The Rosaleen Moldenhauer Memorial: Music History from Primary Sources: A Guide to the Moldenhauer Archives (Washington: Library of Congress, 2000) , which includes a comprehensive inventory. Additionally, the Library of Congress's finding aid  for the Moldenhauer Archives covers Northwestern's holdings as well as the holdings of all other institutions with Moldenhauer materials.