Paper: http://s3.amazonaws.com/fieldexperiments-papers2/papers/00680.pdf http://s3.amazonaws.com/fieldexperiments-papers2/papers/0068... (https://www.nber.org/p

Paper: http://s3.amazonaws.com/fieldexperiments-papers2/papers/00680.pdf http://s3.amazonaws.com/fieldexperiments-papers2/papers/0068... (https://www.nber.org/papers/w26380 https://www.nber.org/papers/w26380)