diff --git a/web/modules/custom/geo_citation/geo_citation.module b/web/modules/custom/geo_citation/geo_citation.module
index 740eb8a..3745a5e 100644
--- a/web/modules/custom/geo_citation/geo_citation.module
+++ b/web/modules/custom/geo_citation/geo_citation.module
@@ -75,7 +75,12 @@ function geo_citation_pseudo_field($entity) {
     return $markup;
   }
 
-  $authors = isset($entity->field_authors->entity) ? $entity->field_authors->entity->title->value : '';
+  $authors = '';
+  foreach ($entity->field_authors as $i => $author) {
+    // @TODO replace this with https://packagist.org/packages/agaric/oxford-comma
+    $authors .= ($i > 0) ? ', ' : '';
+    $authors .= isset($author->entity) ? $author->entity->title->value : '';
+  }
   $date = $entity->field_publication_date->value;
   $year = substr($date, 0, 4);
   $title = $entity->title->value;