turn findCites(el.parentElement)
          }
        } else {
          return undefined;
        }
      };
      var bibliorefs = window.document.querySelectorAll('a[role="doc-biblioref"]');
      for (var i=0; i<bibliorefs.length; i++) {
        const ref = bibliorefs[i];
        const citeInfo = findCites(ref);
        if (citeInfo) {
          tippyHover(citeInfo.el, function() {
            var popup = window.document.createElement('div');
            citeInfo.cites.forEach(function(cite) {
          