Lee, K.;                     Kim, W.;                     Baek, J.;                     Kim, J.    
        A Comparison into the Factors Affecting Urban Rail Systems: Local, Express, and High-Speed Rail in Tunnels at a Great Depth in a Metropolitan Area. Sustainability 2021, 13, 9527.
    https://doi.org/10.3390/su13179527
    AMA Style
    
                                Lee K,                                 Kim W,                                 Baek J,                                 Kim J.        
                A Comparison into the Factors Affecting Urban Rail Systems: Local, Express, and High-Speed Rail in Tunnels at a Great Depth in a Metropolitan Area. Sustainability. 2021; 13(17):9527.
        https://doi.org/10.3390/su13179527
    
    Chicago/Turabian Style
    
                                Lee, Kyujin,                                 Woojin Kim,                                 Junghan Baek,                                 and Junghwa Kim.        
                2021. "A Comparison into the Factors Affecting Urban Rail Systems: Local, Express, and High-Speed Rail in Tunnels at a Great Depth in a Metropolitan Area" Sustainability 13, no. 17: 9527.
        https://doi.org/10.3390/su13179527
    
    APA Style
    
                                Lee, K.,                                 Kim, W.,                                 Baek, J.,                                 & Kim, J.        
        
        (2021). A Comparison into the Factors Affecting Urban Rail Systems: Local, Express, and High-Speed Rail in Tunnels at a Great Depth in a Metropolitan Area. Sustainability, 13(17), 9527.
        https://doi.org/10.3390/su13179527