quickly whipped up something to fetch citing articles from pubmed

fetchCitingRecords

# essentially same as before but now restructured into a function: getCitingPMIDs()

getCitingPMIDs <- function(PMID) {
  lines <- readLines(paste0("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&linkname=pubmed_pubmed_citedin&id=", PMID)) # construct quering URL using the PMID parameter in resTargetRecord, and fetch its contents into object lines
  
  citingPMIDs <- sub("^.*(<Id>)(.*)(</Id>)", "\\2", lines[grep("<Id>", lines)]) # filter out lines in lines that contain <Id> and then filter out the content between <Id> and </Id>.Store in object citingPMIDs
  
  citingPMIDs <- citingPMIDs[-1] # remove first entry in citingPMIDs, which is the target record
return(citingPMIDs)
}

library(RISmed)

resTarget <- EUtilsSummary("10.1371/journal.pone.0166600") # search for your target record (here I used one of my own articled search for by DOI)

resTarget@PMID # the target records PMID is in resTarget@PMID 

citingPMIDs <- getCitingPMIDs(resTarget@PMID)

resCitingRecords <- EUtilsGet(citingPMIDs) # feed citingPMIDs into EUtilsGet to receive their records

resCitingRecords@ArticleTitle # titles of citing articles

annotated it somewhat.