Optimized extraction of polyphenols from leaves of Rosemary (Rosmarinus officinalis L.) grown in Lam Dong province, Vietnam, and evaluation of their antioxidant capacity oleh Nguyen-Kim Minh-Tam, Truong Quoc-Cuong, Nguyen Minh-Thuy, Cao-Thi Bich-Hang, Tong Thanh-Danh, Dao Tan Phat, Tran Thien Hien, Van Tan Lam, Le Xuan-Tien