The Concept of heresy in the Middle Ages, (11th-13th c.): proceedings of the international conference, Louvain, May 13-16, 1973 /
edited by W. Lourdaux, D. Verhelst 
. - Leuven : Leuven University Press,  1983 
. - viii, 232 p.  25 cm. 
 - (Mediaevalia Lovaniensia  ; ser. 1 ; studia 4 )
<br/><label>  ISBN: </label>90-6186-043-1