pmApi2df                Convert xml PubMed bibliographic data into a
                        dataframe
pmApiRequest            Gather bibliographic content from PubMed
                        database using NCBI entrez APIs
pmCitedBy               Find articles that cite a given PubMed article
pmCollect               Collect and process PubMed bibliographic data
                        in one step
pmEnrichCitations       Enrich a PubMed dataframe with citation data
pmFetchById             Fetch PubMed records by PMID
pmQueryBuild            Build a PubMed search query programmatically
pmQueryTotalCount       Count the number of documents returned by a
                        query
pmReferences            Find references cited by a given PubMed article
