https://web-wp.archive.org/web/20150930035102/http:/www.coloradosuzuki.org/csi-students/fees-applications/piano-duets/
Piano Duets - Colorado Suzuki Institute
Update April 2, 2015: Piano Duet Class reservations are now closed for Summer 2015. We look forward to seeing you this summer.
piano duetscoloradosuzukiinstitute
https://repository.duke.edu/dc/hasm?f%5Bsubject_ssim%5D%5B%5D=Vocal+duets+with+piano&sort=title_ssi+asc
Subject: Vocal duets with piano / Historic American Sheet Music / Duke Digital Repository
Provides access to digital images for over 3,000 pieces from the collection, published in the United States between 1850 and 1920.
with piano