Study on the chemical constituents of Penicillium crustosum,an endophytic fungus from Ophiocordyceps sinensis 
JU Feng, LUO Fan, FENG Dan, GUO Da-le, REN Bo, DENG Yun
NATURAL PRODUCT RESEARCH AND DEVELOPMENT . 2021, (7): 1147 -1155 .  DOI: 10.16333/j.1001-6880.2021.7.009