Try this,

use strict;
use warnings;

my %tgs = (

    'articles' => {
                      'Java' => 'How to Program in Java',
                      'Perl' => 'Perl Programming for Biologists',
                      'Python' => {
                          'Programming' =>  q/Expert's Guide to Scala/
+,
                      },
                  },

    'eBooks'  =>  {
                      'Linux' => q/Linux: A Beginner's Guide/,
                  },
);

print $tgs{articles}{Python}{Programming};
[download]

Hope that helps,