Van Heerden, J.H. (Jan Horn), 1957-; Schoeman, N.J. (Nicolaas Johannes)(Bureau for Economic Research and the Graduate School of Business, University of Stellenbosch, 2000)
Wiese, Melanie; Van Heerden, Cornelius Hendrik, 1957-; Jordaan, Yolanda; North, Ernest J.(College of Economic and Management Sciences, University of South Africa, 2009-04)