Daffalla, Ahmed E., 		Lazim, M.E., 		Farah, S.M., AND 		Ahmed, E.A..
" Effect of  nitrogen on seed yield and content and quality of oil of winter grown sunflower (Helianthus annuus L.)" <em>Gezira Journal of Agricultural Science</em> [Online], Volume 11 Number 1 (1 January 2013)