Columbia subject headings:
Cid, approximately 1043-1099--Songs and music.
Operas--Excerpts--Scores.
Operas--Librettos.
Harvard subject headings:
Princeton subject headings:
Cid, approximately 1043-1099--Drama.
Excerpts.
Operas--Excerpts--Scores.
Operas--Librettos.
Operas.
Scores.