(Introduction)
Alle Psallite
(Introduction of the piece, where it comes from, links to the Montpellier Codex and the snogbook)
https://en.wikipedia.org/wiki/Alle_Psallite_Cum_Luya
https://www.cpdl.org/wiki/index.php/Alle_psallite_cum_luya_(Anonymous)
https://en.wikipedia.org/wiki/Montpellier_Codex
Differences in notation
(Compare original, snogbook, and other editions)
Plica in Alle Psallite
What is a Plica
(Notation examples, links to Apel/Lambert)
Performance
References
The notation of polyphonic music, 900-1600 : Apel, Willi ...
https://en.wikipedia.org/wiki/Willi_Apel
