https://aframis.com/glossary/%d8%b3%d8%a7%d8%ae%d8%aa%d8%a7%d8%b1-%da%a9%d8%a7%d8%b1%d9%87%d8%a7%db%8c-%d9%be%d8%b1%d9%88%da%98%d9%87-work-breakdown-structure/