Columbia subject headings:
Gregorian chants.
Mocquereau, André, 1849-1930.
Neumes.
Harvard subject headings:
Gregorian chants.
Mocquereau, André, 1849-1930.
Music--Manuscripts--Facsimiles
Neumes.
Princeton subject headings:
Gregorian chants.
Music--Manuscripts--Facsimiles.
Neumes.