diff --git a/knockout.rx/knockout.rx.d.ts b/knockout.rx/knockout.rx.d.ts
index 71d95d758..4a27f3fed 100644
--- a/knockout.rx/knockout.rx.d.ts
+++ b/knockout.rx/knockout.rx.d.ts
@@ -4,7 +4,6 @@
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
 /// <reference path="../knockout/knockout.d.ts"/>
-/// <reference path="../rx.js/rx.d.ts"/>
 
 interface KnockoutSubscribableFunctions<T> {
 	toObservable(event?: string): Rx.Observable<T>;
@@ -21,6 +20,8 @@ interface KnockoutComputedFunctions<T> {
 }
 
 declare module Rx {
+	interface ISubject<T> { }
+
 	interface Observable<T> {
 		toKoSubscribable(): KnockoutSubscribable<T>;
 		toKoObservable(initialValue?: T): KnockoutObservable<T>;