Accuracy and currency

Where a figure, rule, or mechanism matters to a decision, check it against the primary source before relying on it. No warranty of fitness for that purpose is offered.

Links to other websites

Pages elsewhere are revised on their owners' schedules, not this one's. The destination of a link can drift away from the reason it was added.

Updates to this notice

If any of this changes, the new wording replaces what came before as soon as it appears here.

Contact

Write to [email protected] with any question about what is explained on this website.