Thank you Anaximander. I appreciate it. I am lucky in that I have full access to the University of Wisconsin – Madison library system. The graduate library contains many numismatic references, most of which circulate. I have access to Göbl's Sasanian Numismatics as well as all of the SNS volumes published to date. In addition, when I am on the library's WiFi I have full access to JSTOR. All of this makes it easy to consult and collect reference books and articles.
Tracy