请教小白兔和皮匠老师：
今天收到 uscis 的RFE,要我提供证明我在学校读书期间on-compus工作（ part time(less than 20 hours a week) Title: Peer Tutor 的合法工作证明。请问需提供什么样的证明，如OIS 的信或学校的信之类的。 有什么范文可提供吗？以下是USCIS 信件原文：
A reviw of the record indicates that you were employed as a peer tutor from february 1, 2004 to Dec 1, ,2004.Please provide evidence that the employment was authorized by the service