回复：EB-1B and EB2 NIW 推荐信一问？

I did both EB-1a and EB-1b. I prepared two different copies for the referees to sign. I think there should be a few of differences: the specification of petition classes in the letter and emphasis on the outstanding in OR and on national interests in NIW. In my case I have to emphasize the extraordinary ability in EB-1a letter and outstanding research in EB-1b.