Andrea Sanguinetti sends the following:
Hi, i suggest that in your page of latin chant books you put the following link: http://www.gregofacsimil.net. In that page follow the link ‘RESTITUTIONS’ (in the left part of the page), and you’ll find the whole responsories of officium nocturnum in square notation in pdf files in a transcription according to Hartker manuscript made by D. Crochu & D. Gatté. I think it’s a very important and good work. Regards. Andrea Sanguinetti.
Following the instructions, with my navigation complicated by language and many non-standard characters that do not render properly on my windows laptop, I do find many beautiful PDF files. Perhaps some can explain more about the origin and goal of the project.
"Perhaps some can explain more about the origin and goal of the project."
I can say nothing of its origins, but is seems that one of the goals (or, at least, uses) of this project is to provide the chants for all the responsories for Matins of the Breviarium Romanum (in the version as allowed by Summorum Pontificum). All the PDFs I viewed match the texts perfectly.
Glancing at the entry for the upcoming feast of Sts. Peter and Paul, all eight responsories appear to be there, and the ones for the the current Week after Pentecost, with readings from the Books of Kings, can be found in section 75, "De Libro Regum," under Restitutions > RÉPONS DE L'OFFICE DE NUIT, or more simply at this direct link: http://www.gregofacsimil.net/01-Restitution/Repons/HTML/75-De-Libro-Regum.html
Taking the Responsories to the Lessons of Matins of the 2nd – 11th Weeks after Pentecost as an example, the links on the above linked page refer to:
01 Deus omnium exauditor – Thursday Lesson II
02 Dominus qui eripuit me – Sunday Lesson II / Thursday Lesson III
03 Ego te tuli – Tuesday / Friday Lesson III
04 Montes Gelboe – Friday Lesson II
05 Exaudisti Domine orationem – Monday/Wednesday Lesson II (or Saturday Lesson I on vigils)
06 Domine si conversus – Tuesday Lesson I
07 Audi Domine hymnum – Monday/Wednesday Lesson III / Saturday Lesson II
08 Peccavi super numerum – Wednesday / Saturday Lesson I
09 Recordare Domine testamenti – Monday Lesson I
10 Praeparate corda vestra – Sunday/Thursday Lesson I
11 Factum est dum tolleret – Tuesday Lesson II
There does, however, seem to be an omission of the responsory for Friday Lesson I, "Percussit Saul mille," but the site appears very thorough and I take this to be an oversight rather than something betokening further lapses in content. Though I speak no French, this might be explained by the nature of the site: it seems to me that the project is chiefly concerned with transposing a particular body of old manuscripts.
Cf: http://www.gregofacsimil.net/01-Restitution/Repons/Notes_respon.html