${%$Hash_reference}

##</code><code>##

${\%$Hash_reference}

##</code><code>##

${ ... expression that returns a hash reference ... }{ ... }

##</code><code>##

${ %$Hash_reference }{ ... }

##</code><code>##

${$Hash_reference}{$values[0]} = \@values;

##</code><code>##

$Hash_reference->{$values[0]} = \@values;