Now available!
Covid and supply-chain delays are behind us. More books are on the way soon, but check out these:
Terence Bailey: Hymns of the Medieval Ambrosian Liturgy with Melodies from the Earliest Sources https://medievalmusic.ca/books/978-1-926664-62-0/
Rex Eakins, ed.: The Collected Transmissions of the Masses by Johannes Martini, Vol. 1: Masses I https://medievalmusic.ca/books/978-1-926664-56-9/