Herrman's Ambpr

I had to Google it, but during the research process ran across this:

http://www.busthalfprices.com/index.php

However, it's been my experience that the Heritage Archive is large enough - over 30,000 Bust Half records - to form decent impressions of value for every Overton I've attempted. In fact, I use it as my confirmation resource when attributing them, along with my Overton book.

No real need, to me, to pay money to acquire Bust Half pricing data.