Wickham, C.J..
The mountains and the city : the Tuscan Appennines in the early Middle Ages /

. - Oxford  : Clarendon Press,  1988 
. - XXXIV, 427 p.  22 cm. 
<br/>К.: Бібліогр. : с. 392-409. 
<br/><label>  ISBN: </label>0-19-821966-0