diff --git a/docs/Reference.md b/docs/Reference.md
index dd96832..13e3f4d 100644
--- a/docs/Reference.md
+++ b/docs/Reference.md
@@ -116,6 +116,9 @@ The following methods are supported:
 * `SpanService *setHidden()`
   * specifies that this is hidden Service for the Accessory.  Returns a pointer to the Service itself so that the method can be chained during instantiation.
   
+* `SpanService *addLink(SpanService *svc)`
+  * adds *svc* as a Linked Service.  Returns a pointer to the calling Service itself so that the method can be chained during instantiation.  Note Linked Services are only applicable for select HAP Services.  See HAP R2 documentation for full details.
+  
 * `virtual boolean update()`
   * HomeSpan calls this method upon receiving a request from a HomeKit Controller to update one or more Characteristics associated with the Service.  Users should override this method with code that implements that requested updates using one or more of the SpanCharacteristic methods below.  Method **must** return *true* if update succeeds, or *false* if not.