I have problem with PHP class and function.

My class file is:

```
<?php
class EF_IP{

public function ip_adresa(){

    // dobivanje IP adrese
    if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
        $ip = $_SERVER['HTTP_CLIENT_IP'];
        return $ip;
        } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
            return $ip;
                } else {
                    $ip = $_SERVER['REMOTE_ADDR'];
                    return $ip;
        }
    }
}
?>

```

And i call from other PHP file:

```
EF_IP::ip_adresa();
echo $ip;

```

And i get error:

```
Strict Standards: Non-static method EF_IP::ip_adresa() should not be called statically

```

What i need to do?