Keyscape Analysis of Petrus de Cruce Motet Aunun - Visual comparison of the Medieval piece with a much more modern composition using color to indicate pitch, chord roots, and keys. From Craig Stuart Sapp's Tonal Landscape Gallery at the Stanford University Center for Computer Research in Music and Acoustics.

Petrus de Cruce, (c. 1270 - c. 1300), France - Biographical data, recommended CDs, books and sheet music, and general bibliography from Dr. Estrella's Incredibly Abridged Dictionary of Composers.