diff --git a/htdocs/product/class/api_products.class.php b/htdocs/product/class/api_products.class.php
index 2e0d21b0456..7b19739d10e 100644
--- a/htdocs/product/class/api_products.class.php
+++ b/htdocs/product/class/api_products.class.php
@@ -462,7 +462,7 @@ class Products extends DolibarrApi
 
 		$childsArbo = $this->product->getChildsArbo($id, 1);
 
-		$keys = ['rowid', 'qty', 'fk_product_type', 'label', 'incdec'];
+		$keys = ['rowid','qty', 'fk_product_type', 'label', 'incdec','ref'];
 		$childs = [];
 		foreach ($childsArbo as $values) {
 			$childs[] = array_combine($keys, $values);