groups and families in 21 provinces and cities in southern region of Vietnam, including An Giang, Ba Ria – Vung Tau, Bac Lieu, Ben Tre, Binh Dương, Binh Phuoc, Binh Thuan, Ca Mau, Can Tho, Dong Nai, Dong Thap, Hau Giang, Ho Chi Minh City, Kien Giang, Long An, Ninh Thu...