diff --git a/sections/devops.md b/sections/devops.md
index ee70ff9..4584aaf 100644
--- a/sections/devops.md
+++ b/sections/devops.md
@@ -1301,6 +1301,7 @@ See also [Infrastructure](README.md#infrastructure)
 * [CloudSkiff](https://medium.com/faun/terraform-code-quality-66e6468f50f3) - (2019) Terraform Code Quality | Key Steps to a good quality for your Infrastructure Code.
 * [Sam Savage](https://www.linkedin.com/pulse/terraform-etc-infrastructure-code-kills-devops-sam-savage/) - (2020) Terraform is not Infrastructure As Code and it kills DevOps
 > "why anyone would want to throw away 50 years of developments in computer science and language theory"
+* [Tiexin Guo](https://medium.com/4th-coffee/on-devops-9-infrastructure-as-code-clean-code-terraform-introduction-and-best-practices-5d266132c70a) - (2021) On DevOps — 9. Infrastructure as Code — Clean Code, Terraform Introduction, and Best Practices
 
 ## Travis CI
 * [Tavis CI Docs](https://docs.travis-ci.com/user/common-build-problems/#Troubleshooting-Locally-in-a-Docker-Image) - Troubleshooting Locally in a Docker Image, useful if you have troubles with travis CI