Ultrasonic-assisted Extraction, Antioxidant Activity and Structural Characterization of Polysaccharides from Oenothera Biennis L. LeavesZhou Yong Dong, Xin Song Yin, Shu Lin Liu, Tie Hua Zhang, Hui Ren and Hai Yun TanE3S Web Conf., 189 (2020) 02025DOI: https://doi.org/10.1051/e3sconf/202018902025