https://archive.org/details/hymnologischest00drevgoog
Hymnologische Studien zu Venantius Fortunatus und Rabanus Maurus : Guido Maria Dreves : Free...
Book digitized by Google from the library of Harvard University and uploaded to the Internet Archive by user tpb.
guido maria drevesvenantius fortunatus
https://archive.org/details/analectahymnicam4849drev
Analecta hymnica medii aevi : Dreves, Guido Maria, 1854-1909 : Free Download, Borrow, and Streaming...
Texts of hymns chiefly Latin, notes in German