Create a citation string from package specific BibTex
entries, suitable to be used in Rd files. The entries are
looked in a file named REFERNCES.bib in the package's
root directory (i.e. inst/ in development mode).
Usage
packageReference(key, short = FALSE)
Arguments
key
character vector of BibTex keys
short
logical that indicates if the reference
should be shorten as First Author et al. if it has more
than one author.
Value
a character string containing the text formated BibTex
entries