op III p.227 (1529) ...
http://lila-erc.eu/data/lexicalResources/NLW/id/attestation/30468 <http://www.w3.org/nl/lemon/frac#Attestation>
op III p.227 (1529) ...
op III p.227 (1529) Et abest chorda ditono a chorda: ita tamen, ut in omni Diapason duo hemitonii habeantur, quorum lentore aliarum vocum praefractio compescatur.