Naumann.—History of Music, Vol. I.
Grove.—Dictionary of Music and Musicians. Article on Schools of
Composition, section relating to early French music.
Hope.—Mediæval Music. Technical Explanation of Mensural Music.
Oxford History of Music, Vol. I, pages 74-388. Technical explanation of
measured music.
Luebke.—History of Art, for an account of Byzantine, Romanesque and
Gothic Architecture.
Guizot.—History of France, for an account of Paris in 1100, with a
statement of manners and customs.