Error(s) in re-building vignettes:
  ...
duplicated vignette title:
  ‘Retrieving and Analyzing PubMed Records via easyPubMed’

--- re-building ‘easyPM_vignette_html.Rmd’ using rmarkdown
Quitting from lines 39-50 (easyPM_vignette_html.Rmd) 
Error: processing vignette 'easyPM_vignette_html.Rmd' failed with diagnostics:
1: PCDATA invalid Char value 16
2: Input is not proper UTF-8, indicate encoding !
Bytes: 0x9A 0xEF 0x6D 0x4F
3: Opening and ending tag mismatch: Citation line 814 and Reference
4: expected '>'
5: Opening and ending tag mismatch: ReferenceList line 740 and PubmedData
6: Opening and ending tag mismatch: PubmedData line 698 and PubmedArticle
7: Unescaped '<' not allowed in attributes values
8: attributes construct error
9: Couldn't find end of Start Tag Article line 850
10: Opening and ending tag mismatch: MedlineCitation line 843 and Reference
11: Opening and ending tag mismatch: PubmedArticle line 842 and ReferenceList
12: Opening and ending tag mismatch: PubmedArticle line 443 and PubmedData
13: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
14: Extra content at the end of the document

--- failed re-building ‘easyPM_vignette_html.Rmd’

--- re-building ‘easyPM_vignette_pdf.Rmd’ using rmarkdown
Warning in for (i in seq_len(n)) { :
  closing unused connection 5 (https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&WebEnv=NCID_1_103722850_130.14.18.125_9001_1546365981_1212189049_0MetA0_S_MegaStore&query_key=1&retstart=0&retmax=500&rettype=null&retmode=xml)
Quitting from lines 39-50 (easyPM_vignette_pdf.Rmd) 
Error: processing vignette 'easyPM_vignette_pdf.Rmd' failed with diagnostics:
1: Input is not proper UTF-8, indicate encoding !
Bytes: 0xC0 0x7B 0x2E 0x6E
2: Opening and ending tag mismatch: Citation line 964 and AffiliationInfo
3: Opening and ending tag mismatch: Reference line 963 and Author
4: Opening and ending tag mismatch: Author line 975 and ArticleIdList
5: Opening and ending tag mismatch: ReferenceList line 740 and Reference
6: Opening and ending tag mismatch: PubmedData line 698 and ReferenceList
7: Opening and ending tag mismatch: PubmedArticle line 443 and PubmedData
8: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
9: Extra content at the end of the document

--- failed re-building ‘easyPM_vignette_pdf.Rmd’

SUMMARY: processing the following files failed:
  ‘easyPM_vignette_html.Rmd’ ‘easyPM_vignette_pdf.Rmd’

Error: Vignette re-building failed.
Error: Duplicate vignette titles.
  Ensure that the %\VignetteIndexEntry lines in the vignette sources
  correspond to the vignette titles.
Execution halted