CANTUS, a database for Latin ecclesiastical chant: http://cantusdatabase.org/

Medievel Music Database, La Trobe University: http://www.lib.latrobe.edu.au/MMDB/index.htm

IMSLP Petrucci Music Library, public domain scores online: http://imslp.org/wiki/Main_Page

Sound Effects, an interdisciplinary journal of sound and sound experience: http://www.soundeffects.dk/