Zhao X E,An Z X,Ma B H,et al.Study of transfer t-PA gene to the goat fetal fibroblasts and nuclear transfer [J].Journal of Northwest A&F University(Natural Science Edition),2007,35(1):1-5.
[2]Tsekova K,Dentchev D,Todorova D. Effect of cadmium and copper on the production of citric acid by Aspergillus niger[J]. Folia Microbiol,2000,45(4):331-334.