Columbia subject headings:
Piano music (4 hands)
Songs (Medium voice) with piano, 4 hands.
Vocal duets with piano, 4 hands.
Harvard subject headings:
Piano music (4 hands)
Songs (Medium voice) with piano, 4 hands.
Vocal duets with piano, 4 hands.
Princeton subject headings:
Piano music (4 hands)
Songs (Medium voice) with piano, 4 hands.
Songs.