De institutione musica V.8: Quod reprehendat Ptolomaeus Pythagoricos in numero proportionum.
Ptolemy, however, reproves the Pythagoreans, and the whole demonstration that we set out in the books mentioned, in several ways; in particular because they join the diatessaron and diapente to the sesquitertian and sesquialter, yet apply no consonances at all to the remaining superparticulars, although these are of the same kind.