When scholars (like you) study cinema or literature they engage in a "conversation" with other scholars, by reading their research and responding to it. Scholars respond to other scholars by agreeing with them, disagreeing with them or sometimes agreeing and disagreeing at the same time.
You are primarily interested in the scholarly conversations about the adaptation of literature to cinema in Italy.
To get you started, below, I am listing some books and articles that discuss Italian film adaptation of literature.
Filmmaking by the Book: Italian Cinema and Literary Adaptation by 
From The Novel To The Film: An Exemplary Case: 'The Garden Of The Finzi-Continis By Giogio Bassani by 
Italian Cinema and Modern European Literatures, 1945-2000 by 
Masters of Two Arts: Re-Creation of European Literatures in Italian Cinema by 
Storia cinematografica della letteratura italiana by