1. Nelius Boshoff (corresponding author), Centre for Research on Evaluation, Science and Technology (CREST) and the DSI-NRF Centre of Excellence in Scientometrics and Science, Technology and Innovation Policy (SciSTIP), Stellenbosch University, Stellenbosch, South Africa.
2. Similo Ngwenya, Centre for Research on Evaluation, Science and Technology (CREST) and the DSI-NRF Centre of Excellence in Scientometrics and Science, Technology and Innovation Policy (SciSTIP), Stellenbosch University, Stellenbosch, South Africa.