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)
Kellerman, T. Stephanus; Van der Westhuizen, G.C.A.; Coetzer, Jacobus A.W.; Roux, Cecilia; Marasas, Walter F.O. (Walter Friedrich Otto); Minne, J.A.; Basson, P.A.(Pretoria : The Government Printer, 1980)