diff --git a/RelaxNG/sbml-core/sbml-core-v2.rng b/RelaxNG/sbml-core/sbml-core-v2.rng
index de31cdf5..289bd220 100644
--- a/RelaxNG/sbml-core/sbml-core-v2.rng
+++ b/RelaxNG/sbml-core/sbml-core-v2.rng
@@ -3,12 +3,12 @@
 <grammar xmlns="http://relaxng.org/ns/structure/1.0"
   datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
   
-  <!-- The following are the core SBML data classes -->
+ <!-- The following are the core SBML data classes -->
  <!-- these will all need l3v2 variants -->
 
+ <include href="sbml-simple-types.rng"/>
  <include href="sbml-sbase-l3v2.rng"/>
  <include href="sbml-core-l3v2.rng"/>
-  <include href="sbml-mathml-l3v2.rng"/>
-  
+ <include href="sbml-mathml-l3v2.rng"/> 
  
 </grammar>