Li, X.;                     Xu, C.;                     Cheng, B.;                     Duan, J.;                     Li, Y.    
        Does Environmental Regulation Improve the Green Total Factor Productivity of Chinese Cities? A Threshold Effect Analysis Based on the Economic Development Level. Int. J. Environ. Res. Public Health 2021, 18, 4828.
    https://doi.org/10.3390/ijerph18094828
    AMA Style
    
                                Li X,                                 Xu C,                                 Cheng B,                                 Duan J,                                 Li Y.        
                Does Environmental Regulation Improve the Green Total Factor Productivity of Chinese Cities? A Threshold Effect Analysis Based on the Economic Development Level. International Journal of Environmental Research and Public Health. 2021; 18(9):4828.
        https://doi.org/10.3390/ijerph18094828
    
    Chicago/Turabian Style
    
                                Li, Xinfei,                                 Chang Xu,                                 Baodong Cheng,                                 Jingyang Duan,                                 and Yueming Li.        
                2021. "Does Environmental Regulation Improve the Green Total Factor Productivity of Chinese Cities? A Threshold Effect Analysis Based on the Economic Development Level" International Journal of Environmental Research and Public Health 18, no. 9: 4828.
        https://doi.org/10.3390/ijerph18094828
    
    APA Style
    
                                Li, X.,                                 Xu, C.,                                 Cheng, B.,                                 Duan, J.,                                 & Li, Y.        
        
        (2021). Does Environmental Regulation Improve the Green Total Factor Productivity of Chinese Cities? A Threshold Effect Analysis Based on the Economic Development Level. International Journal of Environmental Research and Public Health, 18(9), 4828.
        https://doi.org/10.3390/ijerph18094828