- https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-capturing-parentheses
- http://regexr.com/
- http://rick.measham.id.au/paste/explain.pl?regex=%2F%5E%28%3F%3D.*%5Cd%29%28%3F%3D.*%5Ba-z%5D%29%28%3F%3D.*%5BA-Z%5D%29%28%3F%3D.*%5B%5Ea-zA-Z0-9%5D%29%28%3F%21.*%5Cs%29.%7B8%2C16%7D%24%2F%3B