BibTex format
@unpublished{LI:2020:10.2139/ssrn.3609516,
author = {LI, J and Guo, X},
doi = {10.2139/ssrn.3609516},
publisher = {Elsevier BV},
title = {Global Deployment Mappings and Challenges of Contact-tracing Apps for COVID-19},
url = {http://dx.doi.org/10.2139/ssrn.3609516},
year = {2020}
}