DOCSP-18495 link to sharding in agg ebook

Author: mungitoperrito

source/core/sharded-cluster-query-router.txt

@@ -379,3 +379,13 @@ Connection Pools
 .. |newversion| replace:: 4.2
 
 .. |oldversion| replace:: 4.0
+
+Using Aggregation Pipelines with Clusters
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For more information on how sharding works with :ref:`aggregations
+<aggregation-framework>`, read the sharding chapter in the `Practical
+MongoDB Aggregations
+<https://www.practical-mongodb-aggregations.com/guides/sharding.html>`__
+e-book.
+ 

source/sharding.txt

@@ -389,12 +389,22 @@ available on sharded clusters.
 
 .. include:: /includes/extracts/transactions-committed-visibility.rst
 
+Learn More
+----------
+
+Practical MongoDB Aggregations E-Book
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For more information on how sharding works with
+:ref:`aggregations <aggregation-framework>`, read the sharding chapter
+in the `Practical MongoDB Aggregations
+<https://www.practical-mongodb-aggregations.com/guides/sharding.html>`__
+e-book.
 
-For details, see:
+Additional Information
+~~~~~~~~~~~~~~~~~~~~~~
 
 - :doc:`/core/transactions`
 - :doc:`/core/transactions-production-consideration`
 - :doc:`/core/transactions-sharded-clusters`
 
-
-