I don't want to mention the researcher's name without his permission. He found the books containing the docuмentary evidence in the Anselmianum library.
That's understandable. But if someone could post copies from the books, that would be great. I did the same type of research at one point. When Bishop Kelly was going around saying that some of the ordinations done by +Lefebvre were invalid because he only laid one hand on the ordinand instead of the two indicated in the rubrics, I went to The Catholic University of America library and found medieval texts in which the rubric for priestly ordination specified only one hand,
dextram. It appeared that the modern reference to the plural was a reference to both the co-ordaining bishops as well as all the priests who also laid their hands on the ordinands.