Edward Maunde Thompson,
A guide to the manuscripts and printed books illustrating the progress of musical notation
(1885)
“ Germany: early 14th century. Breviary, with full choral services, in Latin, of the use of Cologne; four-line stave, red, yellow, and two black. [Add, MS. 31,913.] 26. Italy: 14th century. Gradual, or musical services for the Mass, in Latin; four-line stave. [Add. MS. 18,198.] ”
