diff --git a/src/main/java/PDLayer.mdl b/src/main/java/PDLayer.mdl
index e1671f5..0c207e9 100644
--- a/src/main/java/PDLayer.mdl
+++ b/src/main/java/PDLayer.mdl
@@ -708,6 +708,8 @@ type PDFormField extends PDObject {
 	property TU: String;
 	% value of the Ff entry
 	property Ff: Integer;
+	% link to kids fields
+	link Kids: PDFormField*;
 }
 
 % Form field of type text