docs: function(req, data, name, snippet, field, callback) {
        var manager = self._pages.getManager(field.withType);
        if (!manager) {
          return callback(new Error('join with type ' + field.withType + ' unrecognized'));
        }
        var titlesOrIds = self._apos.sanitizeString(data[name]).split(/\s*,\s*/);
        if ((!titlesOrIds) || (titlesOrIds[0] === undefined)) {
          return setImmediate(callback);
        }
        var clauses = [];
        _.each(titlesOrIds, function(titleOrId) {
          clauses.push({ sortTitle: self._apos.sortify(titleOrId) });
          clauses.push({ _id: titleOrId });
        });
        return manager.get(req, { $or: clauses }, { fields: { _id: 1 }, withJoins: false }, function(err, results) {
          if (err) {
            return callback(err);
          }
          results = results.pages || results.snippets;
          if (field.limit !== undefined) {
            results = results.slice(0, field.limit);
          }
          snippet[field.idsField] = _.pluck(results, '_id');
          return callback(null);
        });
      }