Prior to being assigned to a client company, all employees will be required to produce documents that establish your identity and your employment eligibility. A list of acceptable documents is available at each of our local offices. In addition, if you are to be assigned to a client working at a military installation, you will be required to prove that you are a citizen of the United States. For individuals born in the United States, a birth certificate is the primary and preferred means of citizenship verification. Other documents may also be used to prove citizenship, contact the nearest office for a list.