Columbia subject headings:
Lambertus. Ars musica.
Music theory--Early works to 1800.
Music theory--History--500-1400.
Music--500-1400--History and criticism.
Harvard subject headings:
Lambertus. Ars musica.
Music theory--Early works to 1800.
Music theory--History--500-1400.
Music--500-1400--History and criticism
Princeton subject headings:
Music--Early works to 1800.