● kenjis/codeigniter-doctrine

https://github.com/kenjis/codeigniter-doctrine

● How to install Doctrine in CodeIgniter 3

https://stackoverflow.com/questions/33209930/how-to-install-doctrine-in-codeigniter-3

● CodeIgniter and Doctrine

https://www.doctrine-project.org/projects/doctrine1/en/latest/cookbook/code-igniter-and-doctrine.html