code: function getReference( referenceFile ) {
    var text = '';
  
    // Read references file.
    var referencePath = path.join( process.cwd(), referenceFile );
  
    var stats = fs.statSync( referencePath );
    if (stats && stats.isFile()) {
      text = fs.readFileSync( referencePath, { encoding: 'utf8' } );
  
      // Find common root definitions (tilde references).
      var tildes = { };
      var re = /^\s*\[(~\d*)]\s*:/g;
      var source = text.split( '\n' );
      var target = [ ];
      for (var i = 0; i < source.length; i++) {
        var line = source[ i ].trim();
        // Search common root pattern.
        var result = re.exec( line );
        if (result)
        // Save common root value.
          tildes[ result[ 1 ] ] = line.substring( line.indexOf( ':' ) + 1 ).trim();
        else if (line[ 0 ] === '[')
        // Store reference link.
          target.push( line );
      }
      text = target.join( '\n' );
  
      // Replace tilde+number pairs with common roots.
      var noIndex = false;
      for (var attr in tildes) {
        if (tildes.hasOwnProperty( attr )) {
          if (attr === '~')
            noIndex = true;
          else {
            var re_n = new RegExp( ' ' + attr, 'g' );
            var re_value = ' ' + tildes[ attr ];
            text = text.replace( re_n, re_value );
          }
        }
      }
      // Finally replace tildes with its common root.
      if (noIndex)
        text = text.replace( / ~/g, ' ' + tildes[ '~' ] );
    }
    return text;
  }
docs: Reads the content of a reference file.
  @param {string} referenceFile - The path of the reference file.
  @returns {string} The list of reference links.