Article with an appositive phrase

Please help me understand whether I need an article and why.

*"Companies I have worked with:

• Wolfestone, translation agency (Swansea, UK)
• […]"*

Do I have to place an article before "translation agency"? I feel that if it were in a sentence, I would need an article, but in a list like that (it’s from my CV) I’d better omit it. Is this feeling right or wrong? Are there any rules for such situations?

Thanks in advance!