What do you call a person that works in a public exhibition event?

In a public yearly event that it's all about music and books. Different companies rent a space for exhibition of their services and products. I volunteered in one of those exhibitions, but now i'm trying to fill out my resume of everything I did and I don't know what is exactly the "title name" for when you help in an exhibition....
Please, help me!
Asked Mar 27, 2014

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