Wu, H.C. (How-Chiun); Du Toit, Elsa Sophia; Reinhardt, Carl Frederick (Charlie); Rimando, A.M.; Van der Kooy, Frank; Meyer, Jacobus Johannes Marion(Springer, 2007-07)
Msuya, C.P.; Duvel, G.H. (Gustav Heinrich)(South African Society for Agricultural Extension, Department of Agricultural Ecomomics, Extension and Rural Development, University of Pretoria, 2007)