Microfilms of all chant manuscripts of the Ill.L.Vr.-Broederschap are in the Letterenbibliotheek Utrecht. For several reasons some of the films are inconvenient to use. Unfortunately most of the manuscripts received a foliation only after the film was made. The films of ms 66 and 67 should be read backwards. Besides, some folia are badly legible. And ms 68 has been rearranged and rebound after the film has been made.
Of inv.nrs. 66-71 microfilm prints, provided with modern foliation, and (in case of ms 68) arranged in the right order, are at hand in the Musicology Fotogramarchief of the Letterenbibliotheek Utrecht. Though some illegible parts remain (it must be said that sometimes the films are more clear than the prints), the prints are easier to use than the films.