Refer to conference proceedings published in hard copy in a collection in the same way as a chapter in a collected work.
John, S., Pedro, J., & Nyandoro, O. T. C. (2012). Development of a model-based wheel slip control using feedback linearization. In D. M. Madyira, N. Janse van Rensburg, & A. J. Nel, (Eds.), Conference proceedings (pp. 37-43). 8th South African Conference on Computational and Applied Mechanics (SACAM 2012), Johannesburg, South Africa. South African Association for Computational and Applied Mechanics.
Text reference:
(John et al., 2012).
Many organisations publish their conference presentations on their web pages.
Schlünz, G. I., & Barnard, E. (2013). A discourse model of affect for text-to-speech synthesis. Paper delivered at the 24th annual Symposium of the Pattern Recognition Association of South Africa, Pretoria. http://www.prasa.org/proceedings/2013/prasa2013-14.pdf
Text reference:
(Schlünz, & Barnard, 2013).