Columbia subject headings:
De mensuris et discantu.
Mensural notation.
Music theory--History--500-1400.
Neumes.
Organa.
Harvard subject headings:
Mensural notation.
Mensuris et discantu.
Music theory--History--15th century.
Music theory--History--500-1400.
Neumes.
Organa--History and criticism
Princeton subject headings: