History - Confitebor tibi... in toto

Feb 28, 2022 (fkchaud)

Adding Graduale Romanum 1974 as a source

sources
[{"chant_id":"318","source":"2","page":"155","sequence":"1","extent":"1"},{"chant_id":"318","source":"3","page":"573","sequence":"1","extent":"1"},{"chant_id":"318","source":"4","page":"123","sequence":"1","extent":"1"}]