History - Trium puerorum cantemus
Feb 27, 2021 (Olivier Berten)
Add Hartker source
remarks
https://www.e-codices.unifr.ch/en/csg/0390/151
sources
[{"chant_id":"14739","source":"17","page":"139","sequence":"3","extent":"1"},{"chant_id":"14739","source":"59","page":"151","sequence":"7","extent":"1"}]