{ 
    package Foo::Bar::Baz;
    our $x = 123;
}

##</code><code>##

$ns = 'Foo::Bar::Baz::';
$ref = \${ $::{$ns}{x} };

##</code><code>##

$ns = 'Foo::Bar::Baz';
my $stash = \%::;
foreach(split '::', $ns) {
    $stash = $stash->{"$_\::"};
}

$ref = \${ $stash->{x} };

##</code><code>##

{
    no strict 'refs';
    $ref = \${ "Foo::Bar::Baz::x" };
}