use strict 'refs'

Se puede ser mas especıfico y restringir solo el uso de referencias simbólicas con use strict 'refs':

$ cat symbol_ref2.pl
#!/usr/bin/perl -w

use strict 'refs';

$x = 4; # no se ha usado our
$a = "x"; # $a tampoco es declarada
$$a = 10;

print $x;
$ ./symbol_ref2.pl
Can't use string ("x") as a SCALAR ref while "strict refs" in use at ./symbol_ref2.pl line 7.