Funding for this research was provided by:
Bloomberg Philanthropies
Article History
Received: 18 November 2019
Revised: 29 April 2020
Accepted: 7 June 2020
First Online: 29 July 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: This study did not need ethical approval and informed consent as it only included material available from the public domain.