Columbia subject headings:
Mensural notation--Early works to 1800.
Music theory--Early works to 1800.
Harvard subject headings:
Mensural notation--Early works to 1800.
Mensural notation.
Music theory--Early works to 1800.
Music theory--History--500-1400.
Princeton subject headings:
Mensural notation--Early works to 1800.
Music theory--Early works to 1800.