diff --git a/htdocs/accountancy/class/bookkeeping.class.php b/htdocs/accountancy/class/bookkeeping.class.php
index 9e58ffed942..03ef8e2754b 100644
--- a/htdocs/accountancy/class/bookkeeping.class.php
+++ b/htdocs/accountancy/class/bookkeeping.class.php
@@ -1980,7 +1980,14 @@ class BookKeepingLine
      * @var integer|string date_creation
      */
 	public $date_creation;
-
+    
+	/**
+	 * @var integer|string $date_modification;
+	 */
     public $date_modification;
+    
+    /**
+     * @var integer|string $date_export;
+     */
     public $date_export;
 }