I'm a Masters student applying for a graduate research internship program in US. They require me to send them at least one letter of recommendation (yes, send, not just provide the contact information for references). It's not a problem, I should be able to provide two such letters. However, I can also send some additional documents such as proof of lab experience. I did one intern abroad at a university which is far better (and ranked higher) than my home uni, so it would be good to prove that. The best I can get from there is a "letter of reference" (that's how they titled it) which simply lists the topic of my project, dates, my duties and the fact that I wrote a report after that. No grades, no assessment of my work - perfectly neutral.
The question is: should I enclose such letter in the additional documents section (of course not in the recommendation letters part) or not, as it is believed that a neutral letter is a negative letter? Can it in any way improve my application?
