By Mead, Roger, Curnow, Robert N., Hasted, Anne M.
By Mukiibi, Joseph K.
By Shiferaw, Bekele, Freeman, H, Swinton, Scott
By Chaboussou, Francis, Foley, Grover, Paul, Helena
By Reijntjes, Coen, Haverkort, Bertus, Waters-Bayer, Ann
By Badejo, M. Adetola, Togun Adeniyi, O.
By Gittinger, Professor J. Price
By Willis, Douglas
By Francis Thompson
By Cameron, David Kerr
By Robert McC. Netting
By Carolan, Michael S.
By Davies, Elwyn, Jennifer Davies
By Pimbert, Michel. P.
By Colas
By Federico, Giovanni
By Purseglove, Jeremy
By Blackiston, Howland
By Bollig, Michael, Schnegg, Wotzka, Hans-Peter
By Wallace, Rob, Davis, Mike
By Rant, Phil
By Brigden, Roy
By Withers, Bruce, Vipond, Stanley
By Johnson, Craig, etc.
By Doggett, Hugh
By Bramwell, Martyn, Beckett, Andrew
By Tomlin, C.
By Food and Agriculture Organization, Hasan, Mohammad R.
By Food and Agriculture Organization of the United Nations, Kapetsky, James McDaid, Nath, Shree S.