http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
[compiled] by Percy Dearmer, R. Vaughan Williams, Martin Shaw.
"There are over 200 carols in the book, including unison and four-part arrangements."
From the Howard Mayer Brown, Edward Downes and Mary Schieffelin Book Collections, October 2004.