Columbia subject headings:
Harvard subject headings:
Choruses, Sacred (Mixed voices), Unaccompanied.
Gregorian chants.
Kyrie eleison (Music)
Masses, Unaccompanied.
Motets.
Princeton subject headings:
Choruses, Sacred (Mixed voices), Unaccompanied.
Gregorian chants.
Kyrie eleison (Music)
Masses, Unaccompanied.
Motets.