[1] PSR-7: HTTP message interfaces - PHP-FIG (2020-06-05 00:48:38 +09:00) https://www.php-fig.org/psr/psr-7/

[2] phly, boy, phly :: PSR-7 Accepted! (Matthew Weier O'Phinney著, 2015-05-19 12:00:00 +09:00) https://mwop.net/blog/2015-05-18-psr-7-accepted.html