There are some times, when you just need a quick review of PHP syntax and important functions.
It may be at your interview or just when you started on your some of the best projects of your career. Believe me, even after 7 years in programming line, I keep this handy sheets on my soft-board. It not only helps a quick get-through for the logics but also keeps me revised for the basics of PHP.
Here is the PHP Quick Reference sheet (I call it as PHP Quickie!!) made specially for PHP Developers.
This reference will be useful for both experienced and new developers in PHP.