def index_of_cite(cite)
      cite_parts = cite.split
      author_s = cite_parts.take(cite_parts.size-1).join(' ')
      year_s = cite_parts.last
      @contents.enum_for(:scan, /(#{author_s}#{possessive}?#{year(year_s)})/
                        ).map { Regexp.last_match.begin(0) }
    end
def index_of_cite(cite)
      cite_parts = cite.split
      author_s = cite_parts.take(cite_parts.size-1).join(' ')
      year_s = cite_parts.last
      @contents.enum_for(:scan, /(#{author_s}#{possessive}?#{year(year_s)})/
                        ).map { Regexp.last_match.begin(0) }
    end
Returns array of citation locations (index) in manuscript

     contents = File.read('./spec/testfiles/test.txt')
     PaperCitations.index_cite(contents, 'Peters et al. 2007')
     # => [219, 500]