diff --git a/README.md b/README.md
index 588a163..d01e1e6 100644
--- a/README.md
+++ b/README.md
@@ -111,7 +111,7 @@ Here you will need to know how a network works, how to configure **firewalls**,
 Resources:
 
 - [OSI Model Explained](https://www.cloudflare.com/en-gb/learning/ddos/glossary/open-systems-interconnection-model-osi/) <sup>FREE</sup>
-- [Computer Networking: A Top-Down Approach](https://www.amazon.com/Computer-Networking-Top-Down-Approach-7th/dp/0133594149) <sup>book</sup>
+- [Computer Networking: A Top-Down Approach](https://www.amazon.com/Computer-Networking-Top-Down-Approach-7th/dp/0133594149) <sup>book</sup> [Video Content](https://www.youtube.com/playlist?list=PLByK_3hwzY3Tysh-SY9MKZhMm9wIfNOas)<sup>video</sup>
 - [TCP/IP and Networking Fundamentals for IT Pros](https://www.pluralsight.com/courses/tcpip-networking-it-pros) <sup>Pluralsight course</sup>
 - [DevSecOps : Master Securing CI/CD | DevOps Pipeline](https://www.udemy.com/course/devsecops/) <sup>Udemy course</sup>
 - [Hands-On Security in DevOps: Ensure continuous security, deployment, and delivery with DevSecOps](https://www.amazon.com/Hands-Security-DevOps-continuous-deployment/dp/1788995503) <sup> Book</sup>
@@ -280,6 +280,8 @@ Resources:
 - [Learn SAFe](https://www.scaledagileframework.com/) <sup>FREE</sup>
 - [Learn Automation Testing](https://blog.testproject.io/2020/03/26/automation-testing-for-beginners-ultimate-guide/) <sup>FREE</sup>
 - [GitLab - Beginner's Guide to DevOps](https://page.gitlab.com/resources-ebook-beginners-guide-devops.html) <sup>FREE</sup>
+- [Common SDLC Models](https://www.scaler.com/blog/software-development-life-cycle/#common-sdlc-models) <sup>FREE</sup>
+
 
 ## Additional resources