Keller, D. J. (1959). Fundamentals of Gregorian chant: A basis for class notes and study (5th rev. ed.). Liturgical Press.
Lua i Stíl Chicago (17ú heag.)Keller, Dominic J. Fundamentals of Gregorian Chant: A Basis for Class Notes and Study. 5th rev. ed. Collegeville, Minn.: Liturgical Press, 1959.
Lua MLA (8ú heag.)Keller, Dominic J. Fundamentals of Gregorian Chant: A Basis for Class Notes and Study. 5th rev. ed. Liturgical Press, 1959.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.