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 0x73 0xD5 0x54
2: expected '>'
3: Opening and ending tag mismatch: Country line 673 and Co<f0>s<d5>T
4: PCDATA invalid Char value 16
5: Opening and ending tag mismatch: Citation line 1391 and Reference
6: expected '>'
7: Opening and ending tag mismatch: ReferenceList line 1287 and PubmedData
8: Opening and ending tag mismatch: PubmedData line 1246 and PubmedArticle
9: expected '>'
10: Premature end of data in tag PubmedArticleSet line 3

--- 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 0x03 0x28 0xB7
2: PCDATA invalid Char value 3
3: Opening and ending tag mismatch: Citation line 1980 and ArticleIdList
4: Opening and ending tag mismatch: ArticleId line 2682 and Reference
5: Opening and ending tag mismatch: ArticleIdList line 2681 and ReferenceList
6: Opening and ending tag mismatch: Reference line 2679 and PubmedData
7: Opening and ending tag mismatch: ReferenceList line 2582 and PubmedArticle
8: PCDATA invalid Char value 4
9: PCDATA invalid Char value 16
10: Opening and ending tag mismatch: PubmedData line 2535 and PubmedArticleSet
11: Premature end of data in tag PubmedArticle line 2283
12: 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