In the rich text editor:
@cepera
In a comment:
[cepera](https://chowlings.com/user/cepera)
For Names and Avatars:
In the rich text editor:
%cepera
In a comment:
[![cepera's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/cepera) [cepera](https://chowlings.com/user/cepera)