https://namaa4all.wordpress.com/2011/01/27/%d9%85%d8%b4%d8%a7%d8%b1%d9%8a%d8%b9-%d8%a5%d8%af%d8%a7%d8%b1%d8%a9-%d8%b9%d9%84%d8%a7%d9%82%d8%a7%d8%aa-%d8%a7%d9%84%d8%b9%d9%85%d9%84%d8%a7%d8%a1-customer-relationship-management-%e2%80%93-crm/