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: 0xF0 0x23 0x95 0x42
2: PCDATA invalid Char value 16
3: PCDATA invalid Char value 2
4: PCDATA invalid Char value 29
5: PCDATA invalid Char value 24
6: PCDATA invalid Char value 21
7: PCDATA invalid Char value 7
8: PCDATA invalid Char value 26
9: PCDATA invalid Char value 24
10: PCDATA invalid Char value 16
11: PCDATA invalid Char value 4
12: PCDATA invalid Char value 2
13: PCDATA invalid Char value 3
14: PCDATA invalid Char value 7
15: PCDATA invalid Char value 2
16: PCDATA invalid Char value 3
17: PCDATA invalid Char value 7
18: PCDATA invalid Char value 2
19: PCDATA invalid Char value 2
20: PCDATA invalid Char value 4
21: PCDATA invalid Char value 5
22: PCDATA invalid Char value 5
23: PCDATA invalid Char value 26
24: PCDATA invalid Char value 11
25: PCDATA invalid Char value 7
26: PCDATA invalid Char value 6
27: PCDATA invalid Char value 7
28: PCDATA invalid Char value 7
29: PCDATA invalid Char value 14
30: PCDATA invalid Char value 2
31: PCDATA invalid Char value 3
32: PCDATA invalid Char value 7
33: PCDATA invalid Char value 4
34: PCDATA invalid Char value 8
35: PCDATA invalid Char value 5
36: PCDATA invalid Char value 18
37: PCDATA invalid Char value 11
38: PCDATA invalid Char value 2
39: PCDATA invalid Char value 3
40: PCDATA invalid Char value 3
41: PCDATA invalid Char value 29
42: PCDATA invalid Char value 19
43: PCDATA invalid Char value 8
44: PCDATA invalid Char value 6
45: PCDATA invalid Char value 27
46: PCDATA invalid Char value 8
47: PCDATA invalid Char value 8
48: PCDATA invalid Char value 4
49: PCDATA invalid Char value 7
50: PCDATA invalid Char value 5
51: PCDATA invalid Char value 2
52: PCDATA invalid Char value 16
53: Opening and ending tag mismatch: Citation line 2740 and Journal
54: Opening and ending tag mismatch: AbstractText line 2751 and ISOAbbreviation
55: Opening and ending tag mismatch: Abstract line 2750 and Journal
56: Opening and ending tag mismatch: Reference line 2739 and Article
57: Opening and ending tag mismatch: ReferenceList line 2588 and MedlineCitation
58: Opening and ending tag mismatch: PubmedData line 2541 and PubmedArticle
59: Opening and ending tag mismatch: Citation line 4456 and Reference
60: expected '>'
61: Opening and ending tag mismatch: ReferenceList line 4418 and PubmedData
62: Opening and ending tag mismatch: PubmedData line 4379 and PubmedArticle
63: PCDATA invalid Char value 16
64: PCDATA invalid Char value 6
65: Opening and ending tag mismatch: Article line 5801 and Chemical
66: Opening and ending tag mismatch: MedlineCitation line 5789 and ChemicalList
67: Opening and ending tag mismatch: PubmedArticle line 5788 and MedlineCitation
68: expected '>'
69: Premature end of data in tag PubmedArticleSet line 3

--- 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 0xA3 0x18 0x31
2: expected '>'
3: Opening and ending tag mismatch: Reference line 999 and Referenc<f0>
4: PCDATA invalid Char value 24
5: Opening and ending tag mismatch: ReferenceList line 746 and Reference
6: Opening and ending tag mismatch: PubmedData line 704 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