The markdown citation format is [@RefYY] and the RefYY is the bibtex cite key that is looked up in the source .bib file
Usage of mdcites:
-bib string
required full path to .bib file containing all references that could be cited
-dir string
optional directory containing .md files to process (default "./")
-out string
filename for output .bib file containing only the cited references (default "references.bib")
mdcites extracts markdown citations in the format [@Ref] from .md files and
looks those up in a specified .bib file, and writes the refs to target .bib
file which can then be used by pandoc-citeproc to efficiently process
references.