diff --git a/content/posts/2018-09.md b/content/posts/2018-09.md
index c8bae05a3..b02ef1a37 100644
--- a/content/posts/2018-09.md
+++ b/content/posts/2018-09.md
@@ -367,7 +367,7 @@ dspace=# select item_id from item where in_archive is True and withdrawn is Fals
 
 ## 2018-09-20
 
-- Contact Atmire to ask how we can buy more credits for future development
+- Contact Atmire to ask how we can buy more credits for future development ([#644](https://tracker.atmire.com/tickets-cgiar-ilri/view-ticket?id=644))
 - I researched the Solr `filterCache` size and I found out that the formula for calculating the potential memory use of **each entry** in the cache is:
 
 ```