See also the home page of the Legenda book series Studies In Linguistics

Lepschy, Anna Laura, and Arturo Tosi (eds), Multilingualism in Italy Past and Present, Studies In Linguistics, 1 (Legenda, 2002)

Lepschy, Anna Laura, and Arturo Tosi (eds), Rethinking Languages in Contact: The Case of Italian, Studies In Linguistics, 2 (Legenda, 2006)