An index of Gregorian chant

"This index of textual and musical incipits of over ten thousand plainsong melodies draws its material from modern printed chant books, from five selected manuscripts (the Antiphonals of Lucca and Worcester, and the Graduals of Benevento, St. Yrieix, and Sarum), and from studies of specific categories of chant. The entries in Volume I are arranged in the alphabetical order of the textual incipits and include the melodic incipits of the chant. Volume II indexes chants according to a numeric melodic code devised by Nanie Bridgman."--Publisher's website, volume 1.