https://www.forum.universityupdates.in/threads/official-booking-what-is-the-3-1-1-rule-for-a-carnival-cruise.54806/ https://deskhelpsupport.zohodesk.com/portal/en/kb/articles/official-booking-what-is-the-3-1-1-rule-for-a-carnival-cruise https://deskhelpsupport.zohodesk.com/portal/en/kb/articles/what-is-the-3-1-1-rule-for-a-carnival-cruise