private function getDateFromDublinCore(): ?\DateTime {
        $dt = null;
        $nodes = $this->article()->getRawDoc()->find('*[name="dc.date"], *[name="dc.date.issued"], *[name="DC.date.issued"]');

        /* @var $node Element */
        foreach ($nodes as $node) {
            try {
                if ($node->hasAttribute('content')) {
                    $dt = new \DateTime($node->getAttribute('content'));
                    break;
                }
            }
            catch (\Exception $e) {
                // Do nothing here in case the node has unrecognizable date information.
            }
        }

        if (!is_null($dt)) {
            return $dt;
        }

        return $dt;
    }