diff --git a/app/models/book.rb b/app/models/book.rb
index 319a619..3bbe13e 100644
--- a/app/models/book.rb
+++ b/app/models/book.rb
@@ -40,7 +40,7 @@ class Book
   before_validation :add_http
 
   index({year: -1, :publish_date => -1, :publication_date => -1, _id: -1}, { unique: false, background: false })
-  scope :sort_year_date, ->{ order_by(:year => "desc", :publish_date => "desc", :publication_date => "desc", :id => "desc")) }
+  scope :sort_year_date, ->{ order_by(:year => "desc", :publish_date => "desc", :publication_date => "desc", :id => "desc") }
   scope :sort_for_frontend, ->{ where(:is_hidden=>false).order_by(:year => "desc", :publish_date => "desc", :publication_date => "desc", :id => "desc") }
   def book_paper_type
     self.book_type.title rescue ""