The Washington Post: Masks, cash and apps: How Hong Kong's protesters find ways
to outwit the surveillance state.
[1]https://www.washingtonpost.com/world/asia_pacific/masks-cash-and-apps-how-hon
g-kongs-protesters-find-ways-to-outwit-the-surveillance-state/2019/06/15/8229169
c-8ea0-11e9-b6f4-033356502dce_story.html

References

   1. https://www.washingtonpost.com/world/asia_pacific/masks-cash-and-apps-how-hong-kongs-protesters-find-ways-to-outwit-the-surveillance-state/2019/06/15/8229169c-8ea0-11e9-b6f4-033356502dce_story.html