Keller, D. J. (1959). Fundamentals of Gregorian chant: A basis for class notes and study (5th rev. ed.). Liturgical Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रKeller, Dominic J. Fundamentals of Gregorian Chant: A Basis for Class Notes and Study. 5th rev. ed. Collegeville, Minn.: Liturgical Press, 1959.
एमएलए (8वां संस्करण) प्रशस्ति पत्रKeller, Dominic J. Fundamentals of Gregorian Chant: A Basis for Class Notes and Study. 5th rev. ed. Liturgical Press, 1959.
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