protected function closeFamily(Individual $individual): array
    {
        $xrefs = [];

        foreach ($individual->spouseFamilies() as $family) {
            foreach ($family->children() as $child) {
                $xrefs[] = $child->xref();
            }

            foreach ($family->spouses() as $spouse) {
                $xrefs[] = $spouse->xref();
            }
        }

        foreach ($individual->childFamilies() as $family) {
            foreach ($family->children() as $child) {
                $xrefs[] = $child->xref();
            }

            foreach ($family->spouses() as $spouse) {
                $xrefs[] = $spouse->xref();
            }
        }

        return $xrefs;
    }