Starting in 2014-2015, AAS/IOP started linking to preprints in reference lists if they were the version cited by the author and an accepted manuscript did not at that time exist.

Thus we now have built in "categories" for references, which could be expanded to include data/software sections.

This software citation losts its version information. We will have to work on our typsetting and production rules, as well as develop formal JATS/NLM XML schema to contain versioning information.