Howell, P.G.; Nurton, Jane P.; Nel, Daleen; Lourens, Carina W.; Guthrie, Alan John(Agricultural Research Council, ARC-OVI and the University of Pretoria, 2008-06)
Scheffer, Elizabeth G.; Venter, Gert Johannes; Joone, Christopher; Osterrieder, Nikolaus; Guthrie, Alan John(Agricultural Research Council, ARC-OVI and the University of Pretoria, 2011-11-11)