(2022-Present) Semana de la matematica,University of Buenos Aires (joint with Pablo Groisman).

(Fall 2015-Summer 2016)-Lesiba Maphakela (University of the Witwatersrand).

(Summer 2010)-Luyanda Ndlov (University of the Witwatersrand).

(Summer 2010)-Simphiwe Simelane (University of the Witwatersrand).

(Summer 2010)-Adrian Joseph (University of the Witwatersrand-joint with M. Sears).

(Fall 2010)- Cody Anderson (Georgia Southern).

(Spring 2009)-Jon Martin (Georgia Southern).

(Spring 2008)-Andy Haas (Georgia Southern).

(Spring 2007)-Brandon Bevan.

(Spring 2007)Tommy Rogers and William Triplett (Georgia Southern).

(Spring 2006)-Tommy Rogers, William Triplett (Georgia Southern).