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: expected '>'
2: Opening and ending tag mismatch: Citation line 2262 and Citat
3: Input is not proper UTF-8, indicate encoding !
Bytes: 0xF9 0x1E 0xF3 0x55
4: PCDATA invalid Char value 30
5: Opening and ending tag mismatch: Reference line 2261 and AffiliationInfo
6: Opening and ending tag mismatch: ReferenceList line 1918 and Author
7: Opening and ending tag mismatch: Author line 2281 and Article
8: Opening and ending tag mismatch: PubmedData line 1871 and MedlineCitation
9: Specification mandate value for attribute IdTya
10: Opening and ending tag mismatch: ArticleId line 2587 and Reference
11: Opening and ending tag mismatch: ArticleIdList line 2586 and ReferenceList
12: Opening and ending tag mismatch: Reference line 2584 and PubmedData
13: Opening and ending tag mismatch: ReferenceList line 2571 and PubmedArticle
14: Opening and ending tag mismatch: AbstractText line 2905 and AffiliationInfo
15: Opening and ending tag mismatch: Abstract line 2904 and Author
16: Opening and ending tag mismatch: Author line 2916 and Affiliation
17: Opening and ending tag mismatch: Article line 2884 and AffiliationInfo
18: Opening and ending tag mismatch: MedlineCitation line 2872 and Author
19: Opening and ending tag mismatch: PubmedArticle line 2871 and AuthorList
20: Opening and ending tag mismatch: PubmedData line 2524 and Article
21: Opening and ending tag mismatch: PubmedArticle line 1589 and MedlineCitation
22: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
23: 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 0x53 0x51
2: error parsing attribute name
3: attributes construct error
4: Couldn't find end of Start Tag Ci<f0> line 844
5: Opening and ending tag mismatch: ArticleIdList line 1532 and ReferenceList
6: Opening and ending tag mismatch: Reference line 1530 and PubmedData
7: Opening and ending tag mismatch: ReferenceList line 1295 and PubmedArticle
8: Opening and ending tag mismatch: PubmedData line 1254 and PubmedArticleSet
9: Premature end of data in tag PubmedArticle line 1106
10: 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