Improve EndpointSlice concept

- add links to API references
- tweak initial text

content/en/docs/concepts/services-networking/endpoint-slices.md

@@ -15,11 +15,9 @@ description: >-
 
 {{< feature-state for_k8s_version="v1.21" state="stable" >}}
 
-_EndpointSlices_ provide a simple way to track network endpoints within a
-Kubernetes cluster. They offer a more scalable and extensible alternative to
-Endpoints.
-
-
+Kubernetes' _EndpointSlice_ API provides a way to track network endpoints
+within a Kubernetes cluster. EndpointSlices offer a more scalable and extensible
+alternative to [Endpoints](/docs/concepts/services-networking/service/#endpoints).
 
 <!-- body -->
 
@@ -274,3 +272,5 @@ networking and topology-aware routing.
 ## {{% heading "whatsnext" %}}
 
 * Follow the [Connecting Applications with Services](/docs/tutorials/services/connect-applications-service/) tutorial
+* Read the [API reference](/docs/reference/kubernetes-api/service-resources/endpoint-slice-v1/) for the EndpointSlice API
+* Read the [API reference](/docs/reference/kubernetes-api/service-resources/endpoints-v1/) for the Endpoints API