my %hash = (
             a => 'foo',
             b => 'bar',
             c => 'baz',
             d => 'quux',
           );

print @hash{'a','d'},"\n"; # correctly prints out "fooquux"

my $hashRef = \%hash;

# generates error
# "Not an ARRAY reference at hashArrayPlay.pl line 16."
print @$hashRef->{'a','d'};