my($foo, $bar, $baz) = qw/ one two three /;

my %hash = (
  key1 => \$foo,
  key2 => \$bar,
  key3 => \$baz,
);

## must dereference to get value
print ${ $hash{key1} }, "\n";

$foo = 'something else';

print ${ $hash{key1} }, "\n";

__output__

one
something else