after fixing the brackets like choroba introduced,
i would access and travel the hash like this..

#!"C:\perl\bin\perl.exe" -w
# pragma
use strict;
use warnings;
use diagnostics;

# includes
use Data::Dumper;
use Data::Diver qw( Dive );

# data
my ( $tgs, %tgs );
%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/, },
);
$tgs = \%tgs;

# dive hash
print Dumper $tgs->{articles}->{Python}->{Programming};

# returns:
#
# $VAR1 = 'Expert\'s Guide to Scala';
#
# or
#
print Dumper Dive( $tgs, qw ( articles Python Programming ) );

# returns:
#
# $VAR1 = 'Expert\'s Guide to Scala';
1;
[download]

kindly perlig