There is no limit to the number of batters and bowlers on a team, however players are sometimes chosen with the purpose of maintaining an even distribution of batting and bowling. Substitutions and other game regulations are overseen by the two field umpires, who may refer video reviews to a third umpire off the field. The original concept of limited overs cricket was introduced by John Wisden in 1877 when he published details of an English match played between Cambridge University and London College. The idea was also used by Australian rules football teams at that time but it was not until after the First World War that it became popular among cricketers in England. Today, one-day matches are the most common type of cricket played in a limited overs format. These are divided up into sessions of up to 180 minutes, during which each team has 15 balls to score their targets. In Test cricket, there is no limit on the number of players you can have in a team. A team can have as many batsmen as they like, as long as there are at least two bowlers available. This is because the amount of over-rate running required by modern cricketers makes having more than seven or eight players is impractical. In One Day Internationals (ODIs) and Twenty20 Internationals (T20Is), any team can have as many as fourteen players if they choose. However, this often leads to a shortage of bowlers, so usually only thirteen players are allowed.