- https://stackoverflow.com/questions/35007871/filtering-urls-from-text-with-regex
- https://stackoverflow.com/questions/29275504/boost-spirit-email-address-parser-attribute-generation
- https://tools.ietf.org/html/rfc2822#section-3.4.1
- https://stackoverflow.com/questions/5806520/parse-email-header-with-regex-in-c-sharp
- https://stackoverflow.com/questions/60510667/how-can-i-define-a-raku-grammar-to-parse-tsv-text RAKU
- https://stackoverflow.com/questions/201323/how-to-validate-an-email-address-using-a-regular-expression
- https://stackoverflow.com/questions/58159909/grammar-to-parse-module-specification More Raku
- https://stackoverflow.com/questions/16912229/grammar-vs-regular-expression-for-parsing-urls an attempt to find URLs