History - Misereris omnium

Feb 28, 2022 (fkchaud)

Adding Graduale Romanum 1974 as a source

sources
[{"chant_id":"533","source":"2","page":"87","sequence":"1","extent":"2"},{"chant_id":"533","source":"3","page":"525","sequence":"1","extent":"2"},{"chant_id":"533","source":"4","page":"62","sequence":"1","extent":"2"}]