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

--- re-building ‘easyPM_vignette_html.Rmd’ using rmarkdown
Warning in grep("\\\n$", msg) :
  input string 1 is invalid in this locale
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: 0xF0 0xB3 0xCD 0x4A
2: error parsing attribute name
3: attributes construct error
4: Couldn't find end of Start Tag Ci<f0> line 844
5: PCDATA invalid Char value 3
6: attributes construct error
7: Couldn't find end of Start Tag JournalIssue line 1570
8: Opening and ending tag mismatch: Journal line 1568 and ArticleId
9: expected '>'
10: Opening and ending tag mismatch: MedlineCitation line 1560 and Reference
11: Opening and ending tag mismatch: PubmedArticle line 1559 and ReferenceList
12: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedData
13: 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 grep("\\\n$", msg) :
  input string 1 is invalid in this locale
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 0xB3 0xFA 0xD6
2: expected '>'
3: Opening and ending tag mismatch: ArticleIdList line 2712 and Ar<f0>
4: expected '>'
5: Opening and ending tag mismatch: ReferenceList line 2589 and PubmedData
6: Opening and ending tag mismatch: PubmedData line 2542 and PubmedArticle
7: Opening and ending tag mismatch: ReferenceList line 3143 and PubDate
8: Opening and ending tag mismatch: PubmedData line 3097 and JournalIssue
9: Opening and ending tag mismatch: PubmedArticle line 2889 and Journal
10: Opening and ending tag mismatch: AbstractText line 3397 and PubDate
11: Opening and ending tag mismatch: Abstract line 3396 and JournalIssue
12: Opening and ending tag mismatch: PubmedArticle line 2290 and Journal
13: Opening and ending tag mismatch: PubmedArticleSet line 3 and Article
14: 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