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: Input is not proper UTF-8, indicate encoding !
Bytes: 0x82 0x74 0xEF 0x55
2: expected '>'
3: Opening and ending tag mismatch: ForeName line 2346 and ForeN0H
4: Opening and ending tag mismatch: Author line 2344 and Chemical
5: Opening and ending tag mismatch: AuthorList line 2327 and ChemicalList
6: Opening and ending tag mismatch: MeshHeadingList line 2367 and Author
7: Opening and ending tag mismatch: Article line 2303 and AuthorList
8: Opening and ending tag mismatch: MedlineCitation line 2291 and Article
9: Opening and ending tag mismatch: PubmedArticle line 2290 and MedlineCitation
10: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
11: Extra content at the end of the document

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

--- re-building ‘easyPM_vignette_pdf.Rmd’ using rmarkdown
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: 0xF0 0xC3 0x60 0x58
2: Opening and ending tag mismatch: ArticleTitle line 1129 and Article
3: Opening and ending tag mismatch: Article line 1114 and MedlineCitation
4: Opening and ending tag mismatch: MedlineCitation line 1107 and PubmedArticle
5: Opening and ending tag mismatch: ForeName line 1757 and Author
6: Opening and ending tag mismatch: AffiliationInfo line 1771 and LastName
7: expected '>'
8: Opening and ending tag mismatch: AuthorList line 1619 and Article
9: Opening and ending tag mismatch: Article line 1597 and MedlineCitation
10: Opening and ending tag mismatch: MedlineCitation line 1590 and PubmedArticle
11: expected '>'
12: Premature end of data in tag PubmedArticle line 1106
13: Premature end of data in tag PubmedArticleSet line 3

--- 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