Columbia subject headings:
Music theory--History--500-1400.
Organ (Musical instrument)--Instruction and study--Early works to 1800.
Harvard subject headings:
Bayerische Staatsbibliothek. Manuscript. Cod. lat. 7755.
British Library. Manuscript. Additional 27630.
Counterpoint--15th century.
Counterpoint--500-1400.
Music theory--History--500-1400.
Organ (Musical instrument)--Instruction and study--Early works to 1800.
Princeton subject headings:
Counterpoint.
Music theory--History--500-1400.
Organ (Musical instrument)--Instruction and study--Early works to 1800.