hi @dmpe Good question! What are their authentication requirements? I believe I’ve tried the same web services, and found them to be too much trouble - would be hard to support as I believe they require API key auth as well as checking IP addresses requests come from, only allowing subscribing institutions to access. Is that wrong? I hope so 
I haven’t used CITAN, but from the DESCRIPTION file https://github.com/Rexamine/CITAN/blob/master/DESCRIPTION it does appear the package doesn’t have any dependencies for making http requests, i.e., accessing these web services.