{
  "name": "ISO weeks in every year from 2001 to 2400",
  "desc": "One row per year of a full 400-year Gregorian cycle: the weekday of January 1, whether it is a leap year, the number of ISO weeks (52 or 53), the Monday that starts ISO week 1 and the Sunday that ends the last ISO week, with the week count from each of two independent calculations.",
  "lic": "CC BY 4.0",
  "lic_url": "https://creativecommons.org/licenses/by/4.0/",
  "by": "The Yardstick Almanac",
  "url": "https://theyardstickalmanac.com/calendars/iso-week-number/",
  "from": [
    "Python 3.15.2 documentation, datetime module: date.isocalendar(), date.fromisocalendar() and the strftime() format codes %G, %V, %u, %W and %U (Python Software Foundation License Version 2; read 2026-11-01)",
    "E. M. Reingold and N. Dershowitz, CALENDRICA 4.0, calendar.l, Section: ISO Calendar, iso-long-year? (Apache License 2.0; read 2026-11-01)"
  ],
  "how": "Compiled by The Yardstick Almanac from the data listed",
  "data_by": [
    "Week rule from the Python datetime documentation and CALENDRICA 4.0 (Apache License 2.0); computed 2026-11-01 with two independent date routines, CC BY 4.0"
  ]
}