Do you know where I can find the documentation for this API? I got MLA style working, but I can't get Chicago/Turabian style working. Once I get this working, I plan to switch to this method for DOIs. Thanks!
To clarify, this is using Content Negotiation on the DOI API (i.e. sending 'Accepts' headers). These DOIs are CrossRef's, so requesting those formats via content negotiation is getting metadata from CrossRef.
Nevermind - I found it.
Sorry to hijack this reply; for your URL citations, you may want to integrate with the Internet Archive (archive.org) to get/store the snapshot of the URL/URI you're citing.