Figure_1._Locations_of_the_three_sporting_zones_and_the_solid_red_line_indicates_the_Beijing-Tianjin-Hebei_BTH_boundary_figure_created_with_Google_Earth_Pro.png

Figure 1. Locations of the three sporting zones and the solid red line indicates the Beijing–Tianjin–Hebei (BTH) boundary (figure created with Google Earth Pro)