diff --git a/relaxng.c b/relaxng.c
index eeacae8..fe20bd8 100644
--- a/relaxng.c
+++ b/relaxng.c
@@ -414,6 +414,7 @@
     xmlDocPtr doc;              /* the associated XML document */
     xmlRelaxNGDefinePtr content;        /* the definitions */
     xmlRelaxNGPtr schema;       /* the schema */
+    int externalRef;            /* 1 if an external ref */
 };
 
 
@@ -1970,6 +1971,7 @@
     ret->doc = doc;
     ret->href = xmlStrdup(URL);
     ret->next = ctxt->documents;
+    ret->externalRef = 1;
     ctxt->documents = ret;
 
     /*
@@ -4616,6 +4618,69 @@
 }
 
 /**
+ * xmlRelaxNGParseImportRef:
+ * @payload: the parser context
+ * @data: the current grammar
+ * @name: the reference name
+ *
+ * Import import one references into the current grammar
+ */
+static void
+xmlRelaxNGParseImportRef(void *payload, void *data, xmlChar *name) {
+    xmlRelaxNGParserCtxtPtr ctxt = (xmlRelaxNGParserCtxtPtr) data;
+    xmlRelaxNGDefinePtr def = (xmlRelaxNGDefinePtr) payload;
+    int tmp;
+
+    tmp = xmlHashAddEntry(ctxt->grammar->refs, name, def);
+    if (tmp < 0) {
+        xmlRelaxNGDefinePtr prev;
+
+        prev = (xmlRelaxNGDefinePtr)
+            xmlHashLookup(ctxt->grammar->refs, def->name);
+        if (prev == NULL) {
+            if (def->name != NULL) {
+                xmlRngPErr(ctxt, NULL, XML_RNGP_REF_CREATE_FAILED,
+                           "Error refs definitions '%s'\n",
+                           def->name, NULL);
+            } else {
+                xmlRngPErr(ctxt, NULL, XML_RNGP_REF_CREATE_FAILED,
+                           "Error refs definitions\n",
+                           NULL, NULL);
+            }
+        } else {
+            def->nextHash = prev->nextHash;
+            prev->nextHash = def;
+        }
+    }
+}
+
+/**
+ * xmlRelaxNGParseImportRefs:
+ * @ctxt: the parser context
+ * @grammar: the sub grammar
+ *
+ * Import references from the subgrammar into the current grammar
+ *
+ * Returns 0 in case of success, -1 in case of failure
+ */
+static int
+xmlRelaxNGParseImportRefs(xmlRelaxNGParserCtxtPtr ctxt,
+                          xmlRelaxNGGrammarPtr grammar) {
+    if ((ctxt == NULL) || (grammar == NULL) || (ctxt->grammar == NULL))
+        return(-1);
+    if (grammar->refs == NULL)
+        return(0);
+    if (ctxt->grammar->refs == NULL)
+        ctxt->grammar->refs = xmlHashCreate(10);
+    if (ctxt->grammar->refs == NULL) {
+        xmlRngPErr(ctxt, NULL, XML_RNGP_REF_CREATE_FAILED,
+                   "Could not create references hash\n", NULL, NULL);
+        return(-1);
+    }
+    xmlHashScan(grammar->refs, xmlRelaxNGParseImportRef, ctxt);
+}
+
+/**
  * xmlRelaxNGProcessExternalRef:
  * @ctxt: the parser context
  * @node:  the externlRef node
@@ -4683,6 +4748,8 @@
             if ((docu->schema != NULL) &&
                 (docu->schema->topgrammar != NULL)) {
                 docu->content = docu->schema->topgrammar->start;
+                if (docu->schema->topgrammar->refs)
+                    xmlRelaxNGParseImportRefs(ctxt, docu->schema->topgrammar);
             }
 
             /*
@@ -6157,6 +6224,16 @@
                            "Found forbidden pattern data/except//ref\n",
                            NULL, NULL);
             }
+            if (cur->content == NULL) {
+                if (cur->type == XML_RELAXNG_PARENTREF)
+                    xmlRngPErr(ctxt, cur->node, XML_RNGP_REF_NO_DEF,
+                               "Internal found no define for parent refs\n",
+                               NULL, NULL);
+                else
+                    xmlRngPErr(ctxt, cur->node, XML_RNGP_REF_NO_DEF,
+                               "Internal found no define for ref %s\n",
+                               (cur->name ? cur->name: "null"), NULL);
+            }
             if (cur->depth > -4) {
                 cur->depth = -4;
                 ret = xmlRelaxNGCheckRules(ctxt, cur->content,
@@ -6495,6 +6572,7 @@
                     ctxt);
     }
 
+
     /* @@@@ */
 
     ctxt->grammar = old;
@@ -8815,8 +8893,11 @@
         case XML_RELAXNG_REF:
         case XML_RELAXNG_PARENTREF:
 	    if (define->content == NULL) {
-	    }
-            ret = xmlRelaxNGValidateValue(ctxt, define->content);
+                VALID_ERR(XML_RELAXNG_ERR_NODEFINE);
+                ret = -1;
+	    } else {
+                ret = xmlRelaxNGValidateValue(ctxt, define->content);
+            }
             break;
         default:
             TODO ret = -1;