A lot of these sheet music links are for songs in the public domain.
- OpenScore - Bringing sheet music to life by creating digital interactive editions. Free for everyone, for any purpose, for evermore! By MuseScore and IMSLP / Petrucci Music Library
- Petrucci Music Library
- University of North Texas Music Library Special Collections
- Ukester Brown's Collection of Internet site for vintage sheet music and recordings.
- Digital Tradition Folk Music Database
- Indiana University - Sheet Music Collection
- University of North Texas Music Library
- The Sheet Music Consortium
- The Folktunes Archive -
- William & Gayle Cook Music Library > Collections
- World War II Songs From The Belfer Audio Laboratory And Archive Syracuse University Library
- The American Folk Song Collection