Interesting study about the correlation between a referee's height and the number of cards/PKs issued User JoeHartless, in the /r/referees: news, support, and links for reddit's association football (soccer) referees subreddit, 22 Jun 2020
Referee height influences decision making in British football leagues User Thorgard7330, in the Psychology subreddit, 25 Jan 2020
Referee height influences decision making in British football leagues User westondeboer, in the Reddit Science subreddit, 24 Jan 2020