Source: PL-Wn 12496 IV Graduale cistercienseFolio: 074rSequence: 3Feast: Petri, PauliOffice: MASSGenre: GrVCantus ID: g00006aMode: 5Full text: Pro patribus tuis nati sunt tibi filii propterea populi confitebuntur tibiExternal image link: Image link