Optimization of Ultrasonic Extraction of Ursolic Acid from Paulownia elongata Leaves by Response Surface Methodology
XING Ya-li1, BI Liang-wu1,2*, ZHAO Zhen-dong1,2, XIA Tian-juan1
NATURAL PRODUCT RESEARCH AND DEVELOPMENT . 2015, (2): 301 -305 .  DOI: 10.16333/j.1001-6880.2015.02.022