Using Variables in Docker Compose : Estefanía García Gallardo

https://medium.com/better-programming/using-variables-in-docker-compose-265a604c2006

Docker Compose Environment Variables : Dockers Docs

https://docs.docker.com/compose/environment-variables/

WordPress & Docker : Sebastian Eschweiler

https://medium.com/codingthesmartway-com-blog/wordpress-docker-17595d203052

WordPress Docker Compose : nezhar

https://github.com/nezhar/wordpress-docker-compose

StackOverflow: How to run wp cli in docker-compose.yml : Jplus2 & vstm

https://stackoverflow.com/questions/50999848/how-to-run-wp-cli-in-docker-compose-yml