Article Effects of Different Level of Nitrogen Fertilizer Applicatio...
Article Nitrogen Use Efficiency and Onion Yield Increased with a Pol...
(not mentioned in the abstract but is within the introduction, mentioning the work by others).
Syed, N., Manir, M., Alizai, A. A., & Ghaffoor, A. (2001). Onion shelf life as a function of the levels of nitrogen and potassium application. J. Biol. Sci, 1(2), 71-73.