https://github.com/mtdowling/cron-expression
http://mtdowling.com/blog/2012/06/03/cron-expressions-in-php/
origin - http://www.pipiscrew.com/?p=6362 php-cron-expression-parser
https://github.com/mtdowling/cron-expression
http://mtdowling.com/blog/2012/06/03/cron-expressions-in-php/
origin - http://www.pipiscrew.com/?p=6362 php-cron-expression-parser