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)
Gordon, Stuart J.G.; Bolwell, Charlotte; Rogers, Chris W.; Musuka, Godfrey; Kelly, Patrick; Guthrie, Alan John; Mellor, Philip S.; Chris Hamblin(AOSIS OpenJournals, 2017-11-14)