title: what are the difference between these operators = and =&
body: <p>From <a href="http://www.php.net/manual/en/language.oop5.basic.php" rel="nofollow">php docs </a></p>
  
  <p>I found this but confused totally what are the difference between these operators <code>(= and =&amp;)</code></p>
  
  <pre><code>$instance = new SimpleClass();
  
  $assigned   =  $instance;
  $reference  =&amp; $instance;
  </code></pre>
  
  <p>Can anyone explain about this properly, please?</p>