Some time ago we got a note from the makers of a recent book of chants 
published in Finland.
Cantus sororum is a collection of transcribed medieval chants sung by Brigittine nuns, edited by musicologist Hilkka-Liisa Vuori. If I understand right, the chants were associated with the Little Office of the Blessed Virgin Mary.
Some samples from an album by duo Vox Silentii are on the net:
Transplantatur ab Jericho
Benedicamus in laudem Patris
An article about the material is on-line at the site of Vox Silentii, and the book is available from the editor or from the Catholic Information Center in Helsinki.
You can read the book’s introduction here.