Source: Chrudimský Graduál (Graduale from Chrudim)Siglum: CZ-CHRm 12580Folios: 160v-161vFolio: 160vSequence: 1Full text (or incipit): O beata orbeGenre: SqRubrics2: [De sancta Trinitate]Feast: Transfiguratio Dom.Feast (text): Transfiguratio Dom.Cantus ID: ah09017Form: M