<p>I have heard it mentioned that attaching an extra recommendation is good if it shows something that cannot be shown in the normal two. Typical examples of providers of such recommendations are coaches, bosses, etc. Would a college professor who has taught you provide additional insight that would warrant an additional recommendation? Thanks.</p>
<p>Readers care less about who wrote the recommendation than what the person says in the recommendation. A generic letter, even if from a congressman, is not much useful.</p>