as.tdmurl               Coerce a url to a tdmurl with a specific type
cr_agency               Check the DOI minting agency on one or more
                        dois
cr_citation_count       Lookup article info via CrossRef with DOI and
                        get a citation count.
cr_cn                   Get citations in various formats from CrossRef.
cr_ft_links             Get full text links from a DOI
cr_ft_text              Get full text from a DOI
cr_fundref              Search the CrossRef Fundref API
cr_journals             Search CrossRef journals
cr_licenses             Search CrossRef licenses
cr_members              Search CrossRef members
cr_prefixes             Search CrossRef prefixes
cr_r                    Get a random set of DOI's through CrossRef.
cr_search               Search the CrossRef Metatdata API.
cr_search_free          Search the CrossRef Metatdata for DOIs using
                        free form references.
cr_works                Search CrossRef works (articles)
extract_xpdf            Extract text from a single pdf document.
get_styles              Get list of styles from
                        github.com/citation-style-language/styles
pmid2doi                Get a PMID from a DOI, and vice versa.
rcrossref-defunct       Defunct functions in rcrossref
rcrossref-package       R Client for Various CrossRef APIs.
