Kruckenberg, L. 1998. Sequenz. Die Musik in Geschichte und Gegenwart: Sachteil, edited by L. Kruckenberg, columns 1254-1286. 2nd edn, Kassel.

Kruckenberg, L. 1997. The Sequence from 1050 - 1150: Study of a Genre in Change. University of Iowa, unpublished Ph.D. diss.