A. E. Johnston
Louise Fresco
D. K. Maheshwari
United States. Agricultural Research Service
A. I. Dow
Malcolm J. Hawkesford
C. C. Doughty
Fredrik Wikström
A. D. Day
Ann Salomonson
United States. Crop Reporting Board.
International Horticultural Congress (25th 1998 Brussels, Belgium)
Thomas Fairhurst
Monrovia Nursery Co
'Mathotoane Ramasike