PS11. Substitutions shall be unlimited. Substitutions may be made, with the consent of the referee, at the following times: (a) Prior to a goal kick in either team's favor; (b) After a goal by either team; (c) After an injury, when the referee stops the game, by either team; (d) At half-time, by either team; (e) Prior to a throw-in in favor of the substituting team.