code: def extractNumber str
        match = STDNUMPAT.match str
        return nil unless match
        return (match[1].gsub(/\-/, '')).upcase
      end
docs: Extract the most likely looking number from the string. This will be the first
   string of digits-and-hyphens-and-maybe-a-trailing-X, with the hypens removed
   @param [String] str The string from which to extract an ISBN/ISSN
   @return [String] The extracted identifier