By C.L.A. Leakey, J.B. Wills
By A. Faniran, O. Areola
By Geoff Godden
By Hill, Dennis S., Waller, J. M.
By Food and Agriculture Organization of the United Nations
By Ruck, H.C.
By Agriculture, Fish.& Food, Min.of
By L.P. Smith, B.D. Trafford
By F. Baker, P. Terry
By Richard J. Chancellor
By Food and Agriculture Organization
By Great Britain: Ministry of Agriculture, Fisheries and Food, P.D. Lees
By Lawrence K. Opeke
By Calvin Wyatt Rose
By G. R. Dixon
By J. A. Samson
By R.W. Widdowson (Bourne, Lincolnshire, UK)
By D. L. Ebbels, John Ernest King
By Williams, Colin Norman, etc., Uzo, J. O, Peregrine, W.T.H.
By L. R. Humphreys
By F.S. Hardy, G.D. Watson
By James L. Brewster (Horticulture Research International, Wellesbourne, UK)
By S. J. Kays
By J.D. Acland