under the direction of the late Fr. Roman Bannwart, O.S.B., on Spotify and YouTube; these recordings generally agree with the semi-mensuralist rhythmic theories articulated by Dr. Dirk van Kampen in this article
Note:Most if not all of the following sites presuppose a “nuanced," non-proportional rhythmic interpretation.
Graduale Synopticum - same edition and numbering as the Graduale Authenticum, with different search options
Introits from the Graduale Novum - triplex edition incorporating the melodic corrections of the AISCGre working group published in the journal Beiträge zur Gregorianik; a PDF specimen of volume I, not 100% in accordance with the printed book, is available for download here (copyright status uncertain!)
Graduale Restitutum - Anton Stingl's duplex edition incorporating the AISCGre melodic corrections, arranged according to the novus ordo Roman calendar; normally the same reading as the Graduale Novum
Col Nostro motu proprio of Pope St. Pius X authorizing the Vatican chant edition and permitting the approval of other books only if the variations in the chant come from good manuscripts (paragraph D)
Pietras Dubia & PCED Response (2018) tolerating chant editions and interpretations other than Solesmes/Vatican, no. 24; note that Pérès and his disciples use editions that sometimes differ considerably from the Vatican edition