http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Frere's index to the antiphons of the Sarum antiphoner
edited by Lila Collamore and Joseph P. Metzinger ; with an introduction by Ruth Steiner.
Includes bibliographical references (page 14).
From the Howard Mayer Brown, Edward Downes and Mary Schieffelin book collections, October 2004.