Text and Data Mining valid from 2018-03-20
Received: 4 October 2017
Accepted: 12 March 2018
First Online: 20 March 2018
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the Faculty of Health Sciences, University of Pretoria, South Africa. Protocol number: 290/2013, LS Boyd.
: Not applicable.
: The authors declare that they have no competing interests.
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