diff --git a/SynonymGroup.ts b/SynonymGroup.ts
index 82e3e56..6154775 100644
--- a/SynonymGroup.ts
+++ b/SynonymGroup.ts
@@ -220,7 +220,7 @@ GROUP BY ?date ?title ?mc`;
             materialCitations: [],
           };
           json.results.bindings.forEach((t) => {
-            if (!t.mc || !t.catalogNumber) return;
+            if (!t.mc || !t.catalogNumbers?.value) return;
             const mc = {
               "catalogNumber": t.catalogNumbers.value,
               "collectionCode": t.collectionCodes?.value,
diff --git a/npm-package/package.json b/npm-package/package.json
index c3c0e48..05ee360 100644
--- a/npm-package/package.json
+++ b/npm-package/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@factsmission/synogroup",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "",
   "main": "index.js",
   "scripts": {