diff --git a/externs/readme.md b/externs/readme.md
index 68253b3448..5fe47b5c9f 100644
--- a/externs/readme.md
+++ b/externs/readme.md
@@ -8,7 +8,7 @@ These two files are special externs that belong to ol3, and this document explai
 
 ### Prevent class properties from being renamed
 
-For events, we make properties available to the application. Other than methods, which can be made available by just marking them with the `@api` annotation directly where they are defined, properties need to be added to `oli.js` in addition:
+For events, we make properties available to the application. Methods can be made available by just marking them with the `@api` annotation directly where they are defined; properties should also be added to `oli.js`:
 
 ```js
 /** @interface */
@@ -43,7 +43,7 @@ ol.MapBrowserEvent = function(type, map, browserEvent, opt_frameState) {
 
 ### Override methods in custom classes
 
-For custom subclasses in applications, which can be created using `ol.extends`, the API may want to make certain methods available to override. In addition to marking such methods as `@api`, they need also be added to an interface in `oli.js`:
+For custom subclasses in applications, which can be created using `ol.inherits`, the API may want to make certain methods available to override. In addition to marking such methods as `@api`, they should also be added to an interface in `oli.js`:
 ```js
 /**
  * @interface
@@ -79,6 +79,7 @@ ol.control.Control.prototype.setMap = function(map) {
   // ...
 };
 ```
+See Custom controls example for an example of how this can be used.
 
 ### Export object literals