It's going to be a paleography-intensive rest-of-the-semester for me, as I return to some editing projects. It can be really good to return to, and tarry in, one's roots.
Two weeks ago my teaching assistant kindly Xeroxed off for me Auguste Pelzer's Abréviations latines médiévales. Supplément au Dizionario di abbreviature latine (Paris: Béatrice-Nauwelaerts, 1966)—twice, actually, so that I can have a copy for work and a copy for home. As its name suggests, Pelzer's short book is a supplement to Adriano Cappelli's essential tool, Lexicon abbreviaturarum: dizionario di abbreviature latine ed italiane, which was in its fifth edition when I bought my first copy in 1983. Pelzer based his work on manuscripts at the Vatican Library, with an eye towards medieval philosophical and theological texts.
Well, Cappelli itself is now on-line, and impressively, at Moscow State University. Follow this link. I'm not sure whether used copies of Cappelli are readily available, but this on-line version will certainly be helpful if you've got a computer nearby as you transcribe.
Thanks to Dick Taylor for the link.