<p>I was wondering how submitting extra recommendations works, as well as materials such as art or scientific research. Does Penn even accept supplementary materials? For example, if I wanted to have a football coach write me a third letter in addition to the two required academic teacher evaluations, would I provide the coach with an envelope with an address, and have him mail the letter? For a scientific article that I had published, could I mail the article's abstract to that same address?</p>