The Library of the Medieval Institute. "Codex Calixtinus". University of Notre Dame. Archived from the original on 2008-01-27. Retrieved 2008-02-16. {{cite journal}}: Cite journal requires |journal= (help)
oxfordmusiconline.com
Drabkin, William. "Part (i)". Grove Music Online. Oxford University Press. Retrieved 10 August 2017.
Drabkin, William. "Part (ii)". Grove Music Online. Oxford University Press. Retrieved 10 August 2017.
Drabkin, William. "Part (iii)". Grove Music Online. Oxford University Press. Retrieved 10 August 2017.
Drabkin, William. "Part (iii)". Grove Music Online. Oxford University Press. Retrieved 10 August 2017.
"part". Oxford Companion to Music. Oxford University Press. Retrieved 10 August 2017.
Drabkin, William. "Part (iii)". Grove Music Online. Oxford University Press. Retrieved 10 August 2017.
web.archive.org
The Library of the Medieval Institute. "Codex Calixtinus". University of Notre Dame. Archived from the original on 2008-01-27. Retrieved 2008-02-16. {{cite journal}}: Cite journal requires |journal= (help)