  The main output of the FORCE11 Software Citation working group
(https://www.force11.org/group/software-citation-working-group) was a paper on
software citation principles (https://doi.org/10.7717/peerj-cs.86) published in
September 2016. This paper laid out a set of six high-level principles for
software citation (importance, credit and attribution, unique identification,
persistence, accessibility, and specificity) and discussed how they could be
used to implement software citation in the scholarly community. In a series of
talks and other activities, we have promoted software citation using these
increasingly accepted principles. At the time the initial paper was published,
we also provided guidance and examples on how to make software citable, though
we now realize there are unresolved problems with that guidance. The purpose of
this document is to provide an explanation of current issues impacting
scholarly attribution of research software, organize updated implementation
guidance, and identify where best practices and solutions are still needed.
