Last Updated: Sep 19, 2016 Views: 28
The best source I found for Italian Christmas ornaments is Brenner:
Brenner, Robert. Christmas revisited. 3rd ed. with rev. price guide. Atglen, PA : Schiffer Pub., 2004. 164 p.
(A Schiffer book for collectors). Chapter 5: "Glass Italian ornaments," pp.67-76. There are additional Italian ornaments shown in the glass ornaments section, pp. 116-147.
I have attached several lists of additional resources on this topic.