回复：

A 1.5-page letter stating my qualifications for outstanding professor (in fact a summary of my CV) prepared by me and signed by my department chair. And on the second page, a list of documents (in the oder of qualifications in I-140 instruction: EB1(b) specific criteria, general evidence, ...).

By the way, department chair can sign everything. I hate to get sponsorship from university officers. In this regional university, the higher-rank officers are not interested in sponsoring green card. I tried to get support from them, they send my material to the university attoney. Then wait and wait , forever.. .

Good luck.