diff -r 48d9b3ae9e1a -r 0e40e05048eb plugins/redmine_bibliography/app/models/author.rb
--- a/plugins/redmine_bibliography/app/models/author.rb
+++ b/plugins/redmine_bibliography/app/models/author.rb
@@ -19,6 +19,10 @@
   }
 
   def institution
-    self.authorship.first.institution
+    if self.authorships.first.nil?
+      ""
+    else
+      self.authorships.first.institution
+    end
   end
 end