diff --git a/htdocs/core/modules/asset/modules_asset.php b/htdocs/core/modules/asset/modules_asset.php
index 324ad6a32b1..7cd2f17931b 100644
--- a/htdocs/core/modules/asset/modules_asset.php
+++ b/htdocs/core/modules/asset/modules_asset.php
@@ -89,4 +89,11 @@ abstract class ModeleNumRefAsset extends CommonNumRefGenerator
 	 *  @return string|int<-1,0>			Next value if OK, <=0 if KO
 	 */
 	abstract public function getNextValue($object);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/core/modules/product/mod_codeproduct_leopard.php b/htdocs/core/modules/product/mod_codeproduct_leopard.php
index 81eba6df26c..cc954cace22 100644
--- a/htdocs/core/modules/product/mod_codeproduct_leopard.php
+++ b/htdocs/core/modules/product/mod_codeproduct_leopard.php
@@ -110,8 +110,6 @@ class mod_codeproduct_leopard extends ModeleProductCode
 	 */
 	public function verif($db, &$code, $product, $type)
 	{
-		global $conf;
-
 		$result = 0;
 		$code = strtoupper(trim($code));
 
diff --git a/htdocs/core/modules/product/modules_product.class.php b/htdocs/core/modules/product/modules_product.class.php
index bb9c206ee8a..554d83f3aff 100644
--- a/htdocs/core/modules/product/modules_product.class.php
+++ b/htdocs/core/modules/product/modules_product.class.php
@@ -72,6 +72,7 @@ abstract class ModelePDFProduct extends CommonDocGenerator
 	abstract public function write_file($object, $outputlangs, $srctemplatepath = '', $hidedetails = 0, $hidedesc = 0, $hideref = 0);
 }
 
+
 /**
  * Class template for classes of numbering product
  */
@@ -208,5 +209,8 @@ abstract class ModeleProductCode extends CommonNumRefGenerator
 	 * @param	int<-1,2>		$type		Type of third party (1:customer, 2:supplier, -1:autodetect)
 	 * @return	string						Return string example
 	 */
-	//abstract public function getExample($langs = null, $objproduct = '', $type = -1);
+	public function getExample($langs = null, $objproduct = '', $type = -1)
+	{
+		return '';
+	}
 }
diff --git a/htdocs/core/modules/product_batch/modules_product_batch.class.php b/htdocs/core/modules/product_batch/modules_product_batch.class.php
index e787ee19e39..417245a968f 100644
--- a/htdocs/core/modules/product_batch/modules_product_batch.class.php
+++ b/htdocs/core/modules/product_batch/modules_product_batch.class.php
@@ -89,4 +89,11 @@ abstract class ModeleNumRefBatch extends CommonNumRefGenerator
 	 *  @return string|int<-1,0>		String if OK, <0 if KO
 	 */
 	abstract public function getNextValue($objsoc, $object);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/core/modules/project/modules_project.php b/htdocs/core/modules/project/modules_project.php
index d9b1d9a1758..08cb393dced 100644
--- a/htdocs/core/modules/project/modules_project.php
+++ b/htdocs/core/modules/project/modules_project.php
@@ -92,4 +92,11 @@ abstract class ModeleNumRefProjects extends CommonNumRefGenerator
 	 *  @return  string|int<-1,0>			Value if OK, 0 if KO
 	 */
 	abstract public function getNextValue($objsoc, $project);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/core/modules/stocktransfer/modules_stocktransfer.php b/htdocs/core/modules/stocktransfer/modules_stocktransfer.php
index beeecc06509..a11976bb280 100644
--- a/htdocs/core/modules/stocktransfer/modules_stocktransfer.php
+++ b/htdocs/core/modules/stocktransfer/modules_stocktransfer.php
@@ -90,4 +90,11 @@ abstract class ModeleNumRefStockTransfer extends CommonNumRefGenerator
 	 *  @return string|int<-1,0>			Value if OK, 0 if KO
 	 */
 	abstract public function getNextValue($object);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/core/modules/takepos/mod_takepos_ref_universal.php b/htdocs/core/modules/takepos/mod_takepos_ref_universal.php
index ee33640a412..2affafe14ba 100644
--- a/htdocs/core/modules/takepos/mod_takepos_ref_universal.php
+++ b/htdocs/core/modules/takepos/mod_takepos_ref_universal.php
@@ -103,7 +103,7 @@ class mod_takepos_ref_universal extends ModeleNumRefTakepos
 	 */
 	public function getExample()
 	{
-		global $conf, $langs, $mysoc;
+		global $langs, $mysoc;
 
 		$old_code_client = $mysoc->code_client;
 		$mysoc->code_client = 'CCCCCCCCCC';
diff --git a/htdocs/core/modules/takepos/modules_takepos.php b/htdocs/core/modules/takepos/modules_takepos.php
index 6307bd42e0a..23d587df564 100644
--- a/htdocs/core/modules/takepos/modules_takepos.php
+++ b/htdocs/core/modules/takepos/modules_takepos.php
@@ -44,4 +44,11 @@ abstract class ModeleNumRefTakepos extends CommonNumRefGenerator
 	 * @return	string|int<-1,0>		Next ref value or last ref if $mode is 'last'
 	 */
 	abstract public function getNextValue($objsoc = null, $invoice = null, $mode = 'next');
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/recruitment/core/modules/recruitment/modules_recruitmentcandidature.php b/htdocs/recruitment/core/modules/recruitment/modules_recruitmentcandidature.php
index 5ad0338ad72..7d7bfadd13d 100644
--- a/htdocs/recruitment/core/modules/recruitment/modules_recruitmentcandidature.php
+++ b/htdocs/recruitment/core/modules/recruitment/modules_recruitmentcandidature.php
@@ -74,4 +74,11 @@ abstract class ModeleNumRefRecruitmentCandidature extends CommonNumRefGenerator
 	 *  @return	string|int<-1,0>					Next value if OK, <=0 if KO
 	 */
 	abstract public function getNextValue($object);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }
diff --git a/htdocs/recruitment/core/modules/recruitment/modules_recruitmentjobposition.php b/htdocs/recruitment/core/modules/recruitment/modules_recruitmentjobposition.php
index a9427b7e068..f5c131cd5e3 100644
--- a/htdocs/recruitment/core/modules/recruitment/modules_recruitmentjobposition.php
+++ b/htdocs/recruitment/core/modules/recruitment/modules_recruitmentjobposition.php
@@ -89,4 +89,11 @@ abstract class ModeleNumRefRecruitmentJobPosition extends CommonNumRefGenerator
 	 *  @return string|int<-1,0>					Next value if OK, 0 if KO
 	 */
 	abstract public function getNextValue($object);
+
+	/**
+	 *  Return an example of numbering
+	 *
+	 *  @return     string      Example
+	 */
+	abstract public function getExample();
 }