diff --git a/journals/utils.py b/journals/utils.py
index 1771a39ebfa5997c1404e84956cca8df8b3c2fb9..1f1f0e0bd21261c6a9e11ed714e2036c245da992 100644
--- a/journals/utils.py
+++ b/journals/utils.py
@@ -52,7 +52,7 @@ class JournalUtils(object):
                 'identifier': [
                     {
                         'type': 'doi',
-                        'id': cls.publication.doi_string()
+                        'id': cls.publication.doi_string
                     }
                 ],
                 'link': [