Added ref to MITRE

Author: memildin

articles/security-center/alerts-reference.md

@@ -135,7 +135,7 @@ Understanding the intention of an attack can help you investigate and report the
 
 The series of steps that describe the progression of a cyberattack from reconnaissance to data exfiltration is often referred to as a "kill chain". 
 
-Security Center's supported kill chain intents are:
+Security Center's supported kill chain intents are based on the [MITRE ATT&CK™ framework](https://attack.mitre.org/matrices/enterprise/eh) and described in the table below.
 
 |Intent|Description|
 |------|-------|