<p>If the application doesn't specify who the other letter of rec has to be from?</p>
<p>Yes, but a LOR would probably be more effective if it were written by one of the profs you had for a class or for whom you worked since they would be able to speak personally to the quality of your work, your work ethic and your overall academic performance.</p>
<p>(IIRC, all of D2’s summer program apps asked for letter from one of her science or math profs.)</p>