You won't find any. Masks reduces the spread by the person who has covid, and it only reduces the spread if he wears it at all time, which is going to be the ca

You won't find any. Masks reduces the spread by the person who has covid, and it only reduces the spread if he wears it at all time, which is going to be the case in a study but is never going to be the case in reality. Covid doesn't seem to be only aerosol BTW. The only things that works at an individual level to reduce the risk to catch covid is to talk to less people. Which again is easy to do if it is chosen by the person but not going to happen if this is compulsory. Mask works in theory but don't works when compulsory, social distancing works in theory but don't work when compulsory. Thus the probability that a legit study prove that mask mandate works exists is 0.