map  { anchor( textify($_), { href => $_ } ) }
    grep { /^[A-Z].+/ &&  -f $_ }
    sort { article_sort($a, $b) }
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If possible, I would put the grep before the sort so that you probably have fewer items to sort which takes less time. (more efficient):

    map  { anchor( textify($_), { href => $_ } ) }
    sort { article_sort($a, $b) }
    grep { /^[A-Z].+/ &&  -f $_ }
[download]