--- a/playground/jsonld.js	Mon Apr 30 19:53:03 2012 -0400
+++ b/playground/jsonld.js	Mon Apr 30 19:54:24 2012 -0400
@@ -423,6 +423,7 @@
  *
  * @param input the JSON-LD input.
  * @param [options] the options to use:
+ *          [base] the base IRI to use.
  *          [format] the format to use to output a string:
  *            'application/nquads' for N-Quads (default).
  *          [resolver(url, callback(err, jsonCtx))] the URL resolver to use.
@@ -1817,6 +1818,10 @@
   }
 
   if(_isString(element)) {
+    // property can be null for string subject references in @graph
+    if(property === null) {
+      return;
+    }
     // emit IRI for rdf:type, else plain literal
     var statement = {
       subject: _clone(subject),
@@ -1824,7 +1829,7 @@
       object: {
         nominalValue: element,
         interfaceName: ((property.nominalValue === RDF_TYPE) ?
-          'IRI': 'LiteralNode')
+          'IRI' : 'LiteralNode')
       }
     };
     if(graph !== null) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test-suite/tests/toRdf-0030-in.jsonld	Mon Apr 30 19:54:24 2012 -0400
@@ -0,0 +1,26 @@
+{
+  "@context": {
+    "xsd": "http://www.w3.org/2001/XMLSchema#",
+    "knows": "http://xmlns.com/foaf/0.1/knows",
+    "name": "http://xmlns.com/foaf/0.1/name",
+    "asOf": "http://example.org/asOf"
+  },
+  "@id": "http://example.org/linked-data-graph",
+  "asOf": {"@value": "2012-04-09", "@type": "xsd:date"},
+  "@graph":
+  [
+    {
+      "@id": "http://manu.sporny.org/i/public",
+      "@type": "foaf:Person",
+      "name": "Manu Sporny",
+      "knows": "http://greggkellogg.net/foaf#me"
+    },
+    {
+      "@id": "http://greggkellogg.net/foaf#me",
+      "@type": "foaf:Person",
+      "name": "Gregg Kellogg",
+      "knows": "http://manu.sporny.org/i/public"
+    },
+    "http://www.markus-lanthaler.com/"
+  ]
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test-suite/tests/toRdf-0030-out.nq	Mon Apr 30 19:54:24 2012 -0400
@@ -0,0 +1,7 @@
+<http://manu.sporny.org/i/public> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <foaf:Person> <http://example.org/linked-data-graph> .
+<http://manu.sporny.org/i/public> <http://xmlns.com/foaf/0.1/knows> "http://greggkellogg.net/foaf#me" <http://example.org/linked-data-graph> .
+<http://manu.sporny.org/i/public> <http://xmlns.com/foaf/0.1/name> "Manu Sporny" <http://example.org/linked-data-graph> .
+<http://greggkellogg.net/foaf#me> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <foaf:Person> <http://example.org/linked-data-graph> .
+<http://greggkellogg.net/foaf#me> <http://xmlns.com/foaf/0.1/knows> "http://manu.sporny.org/i/public" <http://example.org/linked-data-graph> .
+<http://greggkellogg.net/foaf#me> <http://xmlns.com/foaf/0.1/name> "Gregg Kellogg" <http://example.org/linked-data-graph> .
+<http://example.org/linked-data-graph> <http://example.org/asOf> "2012-04-09"^^<http://www.w3.org/2001/XMLSchema#date> .

--- a/test-suite/tests/toRdf-manifest.jsonld	Mon Apr 30 19:53:03 2012 -0400
+++ b/test-suite/tests/toRdf-manifest.jsonld	Mon Apr 30 19:54:24 2012 -0400
@@ -179,6 +179,12 @@
       "purpose": "Tests that named graphs containing named graphs flatten to single level of graph naming.",
       "input": "toRdf-0029-in.jsonld",
       "expect": "toRdf-0029-out.nq"
-    }
+    }, {
+      "@type": ["test:TestCase", "jld:ToRDFTest"],
+      "name": "top-level graph with string subject reference",
+      "purpose": "Tests graphs containing subject references as strings.",
+      "input": "toRdf-0030-in.jsonld",
+      "expect": "toRdf-0030-out.nq"
+    }    
   ]
 }