Some titles have "X-ray" and some have "X ray"?

if ($text =~ /Screening Ligands by X[ -]ray Crystallography/) {
                        say "MATCH!";
                }
                else {
                        say "NOPE!";
                }
}
[download]

The square brackets contain a list of characters; if any one of them matches $text at that spot, the match succeeds.