Update README.md

README.md

@@ -71,3 +71,4 @@ All contributions are welcome, please carefully review the [contributing guideli
 - [Living Off the Living Off the Land](https://lolol.farm) - A collection of resources for thriving off the land.
 - [Detection at Scale Podcast | Jack Naglieri](https://podcasts.apple.com/us/podcast/detection-at-scale/id1582584270) - A detection engineering-focused podcast featuring many thought leaders in the specialization.
 - [Cloud Threat Landscape | Wiz](https://threats.wiz.io/all-techniques) - A cloud detection engineering-focused database, that lists threat actors known to have compromised cloud environments, the tools and techniques in their arsenal, and the technologies they prefer to target.
+- [Splunk ES Correlation Searches Best Practices | OpsTune](https://github.com/inodee/threathunting-spl/blob/master/Splunk%20ES%20Correlation%20Searches%20Best%20Practices%20v1.3.pdf) - A highly detailed guide to producing high quality detection content in the Splunk Enterprise Security app.