875—173.21 (90A) General requirements. The commissioner shall not approve bout permits for bouts on Christmas Day. “Battles royal” or bouts in which more than two boxing contestants are to appear in the ring at the same time shall not be approved. In programs where both amateur and professional contestants appear on the same card, there shall be no more than four amateur bouts of three rounds each. The amateur contests shall be under the complete control and supervision of the United States of America Amateur Boxing Federation authority. On each card containing amateur and professional contests, there shall be at least an equal or greater number of bouts of professional boxing. The amateur section of the card shall be held first with at least a 15-minute intermission between the amateur and professional events.