There are also non-ISO variations such as the 445 calendar: https://en.wikipedia.org/wiki/4%E2%80%934%E2%80%935_calendar https://en.wikipedia.org/wiki/4%E2%80%

There are also non-ISO variations such as the 445 calendar: https://en.wikipedia.org/wiki/4%E2%80%934%E2%80%935_calendar https://en.wikipedia.org/wiki/4%E2%80%934%E2%80%935_calendar