Basson, P.A.; Miller, E.S.; Kellerman, T. Stephanus; Albl, P.; Von Maltitz, L.J.F.; Welman, Wilhelmina G.(Published by The Government Printer, Pretoria, 1975)
Marasas, Walter F.O. (Walter Friedrich Otto); Adelaar, T.F.; Minne, J.A.; Van Rensburg, I.B.J.; Burroughs, G.W.; Kellerman, T. Stephanus(Published by the Government Printer, Pretoria, 1972)
Van der Merwe, W.J.J.; Eicker, A.; Marasas, Walter F.O. (Walter Friedrich Otto); Kellerman, T. Stephanus(Published by The Government Printer, Pretoria, 1979)