Admitted to the camp through the Problem of the Month contest (POM): you should have been notified about it via email, and you do not need to obtain a letter of recommendation.
Returning students (attended any previous SigmaCamp or SigmaNext): If you are a returning student, you are not required to submit a letter of recommendation – we already know who you are! You are considered a returning student only if you have attended camps in the U.S. (not Brazil)
New students (not admitted through the POM): Obtain one letter of recommendation from your Mathematics or Science teacher. Only one recommendation letter is required for all camp applications; submit it only once. See full instructions below.