Ross MacDonald from Dundee recently alerted me to the works of Robert Kuehn on the city laws of Medieval Florence. Having had a quick browse through one of them, they would seem to be very useful to anyone interested in the interplay between the ius proprium and the ius commune in medieval "Italy", Florence being an interesting example of a city where the influence of the ius commune was long resisted owing to the strength of local custom.
I take the liberty of posting a link to his works on amazon here.
Another interesting book which recently landed on my desk is the English translation of an Italian work on Tabula Picta. In this fascinating book, Marta Madero has collected many of the important medieval jurists' views on this thorny property-law issue and has demonstrated rather gracefully just how legally innovative they were when dealing with Roman law. Well worth purchasing.
I take the liberty of posting a link to this work on amazon here.