diff --git a/gsap/TweenLite.d.ts b/gsap/TweenLite.d.ts
index fb0e4d61a..ef535e189 100644
--- a/gsap/TweenLite.d.ts
+++ b/gsap/TweenLite.d.ts
@@ -3,6 +3,9 @@
 // Definitions by: VILIC VANE <https://vilic.github.io/>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
+/// <reference path="Core.d.ts" />
+/// <reference path="Ease.d.ts" />
+
 declare class TweenLite {
     constructor(target: any, duration: number, vars: any);
 
diff --git a/gsap/gsap-tests.ts b/gsap/gsap-tests.ts
index 7d941d431..e1740127b 100644
--- a/gsap/gsap-tests.ts
+++ b/gsap/gsap-tests.ts
@@ -1,4 +1,6 @@
-var tween = TweenLite
+/// <reference path="TweenLite.d.ts" />
+
+var tween = TweenLite
     .to(document.getElementById('some-div'), 1, {
         width: '200px',
         height: '200px'