diff --git a/htdocs/expedition/class/expedition.class.php b/htdocs/expedition/class/expedition.class.php
index dee8184ee18d1..7ed035a545fe3 100644
--- a/htdocs/expedition/class/expedition.class.php
+++ b/htdocs/expedition/class/expedition.class.php
@@ -50,6 +50,9 @@ class Expedition extends CommonObject
 	 */
 	public $element="shipping";
 
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
 	public $fk_element="fk_expedition";
 
 	/**
diff --git a/htdocs/expensereport/class/expensereport_ik.class.php b/htdocs/expensereport/class/expensereport_ik.class.php
index 425851cb6e49f..9eaa8970a5b42 100644
--- a/htdocs/expensereport/class/expensereport_ik.class.php
+++ b/htdocs/expensereport/class/expensereport_ik.class.php
@@ -39,6 +39,9 @@ class ExpenseReportIk extends CoreObject
 	 */
 	public $table_element='expensereport_ik';
 
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
 	public $fk_element='fk_expense_ik';
 
 	/**
diff --git a/htdocs/expensereport/class/expensereport_rule.class.php b/htdocs/expensereport/class/expensereport_rule.class.php
index 8599cfcc81081..6d2a99d2101fe 100644
--- a/htdocs/expensereport/class/expensereport_rule.class.php
+++ b/htdocs/expensereport/class/expensereport_rule.class.php
@@ -33,12 +33,15 @@ class ExpenseReportRule extends CoreObject
 	 * @var string ID to identify managed object
 	 */
 	public $element='expenserule';
-	
+
 	/**
 	 * @var string Name of table without prefix where object is stored
 	 */
 	public $table_element='expensereport_rules';
-	
+
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
 	public $fk_element='fk_expense_rule';
 
 	/**
diff --git a/htdocs/holiday/class/holiday.class.php b/htdocs/holiday/class/holiday.class.php
index 5107ffb09ab0f..39eb2b023de56 100644
--- a/htdocs/holiday/class/holiday.class.php
+++ b/htdocs/holiday/class/holiday.class.php
@@ -43,7 +43,12 @@ class Holiday extends CommonObject
 	public $table_element='holiday';
 
 	public $ismultientitymanaged = 0;	// 0=No test on entity, 1=Test with field entity, 2=Test with link by societe
+
+	/**
+	 * @var int Field with ID of parent key if this field has a parent
+	 */
 	public $fk_element = 'fk_holiday';
+
 	public $picto = 'holiday';
 
 	/**
diff --git a/htdocs/user/class/user.class.php b/htdocs/user/class/user.class.php
index 9020cd3a4bcb7..97172214dc66e 100644
--- a/htdocs/user/class/user.class.php
+++ b/htdocs/user/class/user.class.php
@@ -64,7 +64,12 @@ class User extends CommonObject
 	public $skype;
 	public $job;			// job position
 	public $signature;
+
+	/**
+	 * @var string Address
+	 */
 	public $address;
+
 	public $zip;
 	public $town;
 	public $state_id;		// The state/department