vancouver.csl

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    <title>Vancouver</title>
    <id>http://www.zotero.org/styles/vancouver</id>
    <link href="http://www.zotero.org/styles/vancouver" rel="self"/>
    <author>
      <name>Michael Berkowitz</name>
      <email>mberkowi@gmu.edu</email>
    </author>
    <contributor>
      <name>Sean Takats</name>
      <email>stakats@gmu.edu</email>
    </contributor>
    <contributor>
      <name>Sebastian Karcher</name>
    </contributor>
    <category field="medicine"/>
    <category citation-format="numeric"/>
    <updated>2008-09-16T00:00:00+00:00</updated>
    <summary>
      Vancouver style as outlined by International Committee of Medical Journal Editors Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Sample References
    </summary>
    <link href="http://www.nlm.nih.gov/bsd/uniform_requirements.html" rel="documentation"/>
    <rights>This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License: http://creativecommons.org/licenses/by-sa/3.0/</rights>
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how to incorporate vancouver.csl into knitr?
error generated

pandoc-citeproc: PandocResourceNotFound "vancouver.csl"
Error running filter /usr/lib/rstudio/bin/pandoc/pandoc-citeproc:
Filter returned error status 1
Error: pandoc document conversion failed with error 83
Execution halted

You'll want to ask this on an R/R-studio help forum. I'd suggest stackoverflow. Be sure to provide a minimal example.