diff --git a/README.md b/README.md
index 9605dfa..d53231e 100644
--- a/README.md
+++ b/README.md
@@ -26,17 +26,25 @@ interface IProps {
 }
 
 export const Counter: React.FC<IProps> = ({ start }) => {
-
   const [ value ] = useObservable(() => {
-    return rxjs.interval(1000)
-      .pipe(
-        map(v => v + start),
-        startWith(start),
-      );
-  }, [start])
+    return rxjs.interval(1000).pipe(
+      map(v => v + start),
+      startWith(start)
+    );
+  }, [/* deps */])
 
   return (
-    <p>Started with {start}, value: {value}</p>
+    <p>Started with undefined, value: {value}</p>
   );
 }
-```
\ No newline at end of file
+```
+
+## API
+
+|                     Hook                      |                Return                 |                                                                                               Description                                                                                                |
+| --------------------------------------------- | ------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| useObservable(Func, DepsArray)                | Value, Error, Completed               | Run the observable function on every deps change, the first value will be undefined                                                                                                                      |
+| useRetryableObservable(Func, DepsArray)       | Value, Error, Completed, RetryFunc    | Same useObservable, but the last value of return is a retry function to rerun the observable function, useful when an error happens or do a refresh                                                      |
+| useMappedObservable(Func, MapFunc, DepsArray) | Value, Error, Completed               | Same useObservable, but with a internal map and a distinctUntilChanged, useful to do less renders                                                                                                        |
+| useCallbackObservable(Func, DepsArray)        | CallbackFunc, Value, Error, Completed | Same useObservable, but the first result is the callbackFunction and run the observable function only when it is called, useful to use in a submit or button's click and keep the unsubscribe on unmount |
+
diff --git a/src/callbackObservable.ts b/src/callbackObservable.ts
index ab64d48..ee85cf5 100644
--- a/src/callbackObservable.ts
+++ b/src/callbackObservable.ts
@@ -11,7 +11,7 @@ import { useObservable } from './observable';
 export function useCallbackObservable<T extends (...args: any[]) => Observable<any>>(
   observableGenerator: T,
   deps: DependencyList
-): [() => void, T | undefined, any, boolean] {
+): [() => void, T | undefined, any, boolean, undefined] {
   const [error, setError] = useState();
   const submitted$ = useRef(new Subject<any>()).current;
 
@@ -31,5 +31,5 @@ export function useCallbackObservable<T extends (...args: any[]) => Observable<a
 
   const callback = useCallback((...args: any[]) => submitted$.next(args), [submitted$]);
 
-  return [callback, data, error, completed] as [typeof callback, T | undefined, any, boolean];
+  return [callback, data, error, completed, undefined];
 }
diff --git a/src/mappedObservable.ts b/src/mappedObservable.ts
index 44bc2ac..aae6bd7 100644
--- a/src/mappedObservable.ts
+++ b/src/mappedObservable.ts
@@ -12,7 +12,7 @@ export function useMappedObservable<T, W>(
   observableGenerator: observerFunction<T>,
   mapperFunction: (data: T) => W,
   deps: DependencyList
-): [W | undefined, any, boolean] {
+): [W | undefined, any, boolean, undefined] {
   const newGenerator = useCallback(() => {
     return observableGenerator().pipe(
       map(mapperFunction),
diff --git a/src/observable.ts b/src/observable.ts
index 6b00fa3..047bf2c 100644
--- a/src/observable.ts
+++ b/src/observable.ts
@@ -10,7 +10,7 @@ export type observerFunction<T> = () => Observable<T>;
 export function useObservable<T>(
   observableGenerator: observerFunction<T>,
   deps: DependencyList
-): [T | undefined, any, boolean] {
+): [T | undefined, any, boolean, undefined] {
   const [value, setValue] = useState<T>();
   const [error, setError] = useState();
   const [complete, setComplete] = useState<boolean>(false);
@@ -36,5 +36,5 @@ export function useObservable<T>(
     return () => sub.unsubscribe();
   }, [cb]);
 
-  return [value, error, complete];
+  return [value, error, complete, undefined];
 }
diff --git a/src/retryableObservable.ts b/src/retryableObservable.ts
index 2a99677..98bdcd3 100644
--- a/src/retryableObservable.ts
+++ b/src/retryableObservable.ts
@@ -9,10 +9,10 @@ import { observerFunction, useObservable } from './observable';
  * retry function
  * @returns [observableValue, error, isCompleted, retryFunction]
  */
-export function useRetryableObservable<T, W>(
+export function useRetryableObservable<T>(
   observableGenerator: observerFunction<T>,
   deps: DependencyList
-): [W | undefined, any, boolean, () => void] {
+): [T | undefined, any, boolean, () => void, undefined] {
   const [data, setData] = useState();
   const [error, setError] = useState();
   const submitted$ = useRef(new BehaviorSubject<boolean>(true)).current;
@@ -35,5 +35,5 @@ export function useRetryableObservable<T, W>(
 
   const retry = useCallback(() => submitted$.next(true), [submitted$]);
 
-  return [data, error, completed, retry] as [W | undefined, any, boolean, typeof retry];
+  return [data, error, completed, retry, undefined];
 }