Text and Data Mining valid from 2019-07-08
Received: 29 December 2018
Accepted: 25 June 2019
First Online: 8 July 2019
Ethics approval and consent to participate
: The Human Research Ethics Committee of the University of the Witwatersrand, Johannesburg, South Africa, granted approval for this research. All participants signed an informed consent form.
: Not applicable.
: The authors declare that they have no competing interests.