diff --git a/lib/index.ts b/lib/index.ts
index f438ce7..87c0236 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -1,4 +1,7 @@
+import type * as RDF from '@rdfjs/types';
 import { RdfParser } from './RdfParser';
+
 export * from "./RdfParser";
+
 // tslint:disable:no-var-requires
-export default <RdfParser> require('../engine-default');
+export default <RdfParser<RDF.Quad>>require('../engine-default');