http://www.schaffter.com/cpu/tz.html
http://www.merlyn.demon.co.uk/uksumtim.htm

EU Summer Time:
   Begin    March (31 - (5*y div 4 + 4) mod 7) at 01:00 UTC
   End    October (31 - (5*y div 4 + 1) mod 7) at 01:00 UTC

US DST:
   Begin    April (07 - (5*y div 4 + 4) mod 7) at 02:00 local
   End    October (31 - (5*y div 4 + 1) mod 7) at 02:00 local

usStd = ();
euStd = ()

tzstd = [
"Y", "X", "W", "-9", "-8", "-7", "-6", "-5", "-4", "-3", "-2", "-1",
"0",
"1",   "2",   "3"   "4",  "5",  "6",  "7",  "8",  "9",  "10", "11", "12"
]

tzstd = [
"Y", "X", "HST", "AKST", "PST", "MST", "CST", "EST", "AST", "P", "AT", "WAT"
"GMT", "CET", "EET", "BT", "ZP4", "ZP5", "ZP6", "ZP7", "WAST", "JST", "EAST", "L", "IDLE"