Before revision: These nautical letters have been added to some time zone maps, like the World Time Zone Map published by Her Majesty's Nautical Almanac Office (NAO), which extended the letters by adding an asterisk (*), a dagger (†) or a dot (•) for areas that do not use a nautical time zone (areas that have a half-hour or quarter-hour offset, and areas that have an offset greater than 12 hours), and a section sign (§) for areas that do not have a legal standard time (the Greenland ice sheet and Antarctica).
After revision: These nautical letters have been added to some time zone maps, like the World Time Zone Map published by HM Nautical Almanac Office (NAO), which extended the letters by adding an asterisk (*), a dagger (†) or a dot (•) for areas that do not use a nautical time zone (areas that have a half-hour or quarter-hour offset, and areas that have an offset greater than 12 hours), and a section sign (§) for areas that do not have a legal standard time (the Greenland ice sheet and Antarctica).