Here is a link to a project that is making some 16 & 17th century numismatic books available online-
http://tn.khi.fi.it/index.php?id=7&L=1I don't believe that the modern collector of Late Roman Bronzes will find anything very useful, but maybe there might be something interesting.
Below is a page with some line drawings of Constantinian coinage from the 1641 book by Francesco Angeloni
La Historia Avgvsta Da Giulio Cesare infino à Costantino il Magnoand Goltzius 1557
