There are polls released almost daily pertaining to the Democratic nomination. In order to attend the September 12–13 round of round of debates, candidates need to get donations from 130,000 unique donors and at least 2% in 4 polls (national or early state) from some list of approved pollsters. All polls must be after June 28th.
I like to look up the results of the polls as they are released (realclearpolitics) but have no idea who are the approved pollsters and (if applicable) which of their polls count. I have attempted to google this but keep finding news articles explaining the information above instead of answering this question.