In a reply to my last post, someone posted a link to the YouTube channel of Pierre-Emmanuel Desmaizières, whose videos display the same chants available on the Gregor und Taube website, but with French instead of German translations. Fr. Anthony Ruff has posted images here from the same collection, but without translations. Where can these resources to be found online? As far as I can tell, they are the chants of the Graduale novum without the Laon neumes.