Doyer, O.T.; D'Haese, M.F.C. (Marijke); Kirsten, Johann F.; Van Rooyen, C.J. (Cornelius Johannes)(Agricultural Economics Association of South Africa, 2007-12)
Sartorius, Kurt; Kirsten, Johann F.(Independent Regulatory Board for Auditors (IRBA), SA Institute of Chartered Accountants (SAICA) & SA Association of Accountants (SAAA), 2004-06)
D'Haese, M.F.C. (Marijke); Calus, M.; Kirsten, Johann F.; Van Huylenbroeck, Guido; Bostyn, F.(Agricultural Economics Association of South Africa, 2001-12)