How to link from project code to its Wiki in Markdown?


We’re using Gitlab EE 9.2.6. When I have a Markdown document in the normal code repository, is there a good way to link to the Wiki that the project has?

Or do I have to link to the Wiki using the full URL, eg.


Is there also the other way around? Is there an easy and stable way, to link from a projects Wiki to its code?