vo is not a scientist or a professional in your field. so we should prepare our documents in a pop way, thru which vo could understant your work's significance easily. for vo, he/she doesn't know which journal is best, whose work is best. so he/she make a judgement based on your citation, your reference letters, and othe comments, such as the comments from journal reviewers when you published your paper, which he/she counts more than the reference letters, the commentaries of medium reports. niw, eb1 have different criteria. please refer to the uscis website and I-140 form instructions. follow the instructions when you pack the documents to uscis.