Update guidelines.md

Author: eduardo-rodrigues

projects/guidelines.md

@@ -77,8 +77,8 @@ The review can even be done [directly in a browser](https://learn.scientific-pyt
 ## Differentiated Software Best Practices
 
 Recognising that not all software is the same is very important to ensure that
-appropriate guidelines are applied. Here we adopt roughly the *three levels of
-software*, originally developed by the
+appropriate guidelines are applied. Here we adopt roughly the [*three levels of
+software*](https://everse.software/RSQKit/three_tier_view), originally developed by the
 [Australian Research Data Commons](https://ardc.edu.au/) (ARDC)
 and subsequently adopted by the [EVERSE Project](https://everse.software).