Columbia subject headings:
Gregorian chants.
Sacred vocal duets.
Sacred vocal trios.
Harvard subject headings:
Christian pilgrims and pilgrimages--Spain--Santiago de Compostela.
Gregorian chants.
James, the Greater, Saint--Cult.
James, the Greater, Saint--Songs and music.
Music--Spain--500-1400.
Part songs, Sacred--500-1400.
Sacred vocal music--Spain--500-1400.
Santiago de Compostela (Spain)--Music.
Princeton subject headings: