Joubert, C.S.; Schoeman, N.J. (Nicolaas Johannes); Blignaut, James Nelson(Faculty of Economic and Management Sciences, University of Pretoria, 1999-03)
Van Heerden, J.H. (Jan Horn), 1957-; Blignaut, James Nelson; Groenendijk, N.S.(Faculty of Economic and Management Sciences, University of Pretoria, 1999-06)