diff --git a/rx.js/rx.d.ts b/rx.js/rx.d.ts
index b2ad79a48..a9125dd13 100644
--- a/rx.js/rx.d.ts
+++ b/rx.js/rx.d.ts
@@ -30,7 +30,7 @@ declare module Rx {
 		}
 
 		export class ScheduledItem<TTime> {
-			constructor(scheduler: IScheduler, state: any, action: (scheduler: IScheduler, state) => IDisposable, dueTime: TTime, comparer?: (x: TTime, y: TTime) => number);
+			constructor(scheduler: IScheduler, state: any, action: (scheduler: IScheduler, state: any) => IDisposable, dueTime: TTime, comparer?: (x: TTime, y: TTime) => number);
 
 			scheduler: IScheduler;
 			state: TTime;
@@ -182,7 +182,7 @@ declare module Rx {
 		exception: any;
 
 		static createOnNext<T>(value: T): Notification<T>;
-		static createOnError<T>(exception): Notification<T>;
+		static createOnError<T>(exception: any): Notification<T>;
 		static createOnCompleted<T>(): Notification<T>;
 	}
 
diff --git a/rx.js/rx.virtualtime.d.ts b/rx.js/rx.virtualtime.d.ts
index 9167f0fab..293343fda 100644
--- a/rx.js/rx.virtualtime.d.ts
+++ b/rx.js/rx.virtualtime.d.ts
@@ -11,13 +11,13 @@ declare module Rx {
 	export /*abstract*/ class VirtualTimeScheduler<TAbsolute, TRelative> extends Scheduler {
 		constructor(initialClock: TAbsolute, comparer: (first: TAbsolute, second: TAbsolute) => number);
 
-		advanceBy(time: TRelative);
-		advanceTo(time: TAbsolute);
-		scheduleAbsolute(dueTime: TAbsolute, action: () => void);
+		advanceBy(time: TRelative): void;
+		advanceTo(time: TAbsolute): void;
+		scheduleAbsolute(dueTime: TAbsolute, action: () => void): IDisposable;
 		scheduleAbsoluteWithState<TState>(state: TState, dueTime: TAbsolute, action: (scheduler: IScheduler, state: TState) => IDisposable): IDisposable;
 		scheduleRelative(dueTime: TRelative, action: () => void): IDisposable;
 		scheduleRelativeWithState<TState>(state: TState, dueTime: TRelative, action: (scheduler: IScheduler, state: TState) => IDisposable): IDisposable;
-		sleep(time: TRelative);
+		sleep(time: TRelative): void;
 		start(): IDisposable;
 		stop(): void;