diff --git a/lib/opds-parser.js b/lib/opds-parser.js
index <HASH>..<HASH> 100644
--- a/lib/opds-parser.js
+++ b/lib/opds-parser.js
@@ -544,7 +544,7 @@ OpdsParser.prototype.getFeedType = function(json, callback) {
   function isAcquisition(json, callback) {
     callback(
       json.links.some(function(l) {
-        return l['@'].rel.indexOf('http://opds-spec.org/acquisition') >= 0;
+        return (l['@'].hasOwnProperty('rel') && (l['@'].rel.indexOf('http://opds-spec.org/acquisition') >= 0));
       })
     )
   }
fixing isAcquisition behavior.

link which has no rel attribute will be correctly handled.