" Interestingly, the objects from Italy form a quite homogeneousgroup regarding both their chemical composition and their lead isotope ratios. A comparison with published analyses of copper ores allows us to exclude the northern Alpine, the Sardinian and the Tuscan ore depositsnot sure if i am attaching this right
it is from one of the first two links (lead isotope analysis), there is another r.jung paper that mentions the production/slag site (in the alps) of the sardinian ores and also a north>south transport along the adriatic coast; i saw that paper on sardinian copper in scandinavia, i remember its decline being correlate to the beginnings of iron in italy (initially linked to sardinia as well) prob indicating the network being via italy altogether;
At the same time, there is analytical evidence for a southern Alpine origin of the copper used in Italian bronze production. The majority of the studied objects from Italy are characterised by lead isotope ratios, which coincide with those of contemporaneous copper smelting slags from various work-shop sites in the Trentino"
Doesn't this mean that the Italian objects were not made with Sardinian copper?
By the way Sardinian copper was also used for some objects found in the Eastern Mediterranean and dated to the late bronze age.