Wasaya, Allah, et al. “Tillage Systems and Nitrogen Timings Effect on Growth, Stay Green and Grain Quality in Maize (Zea Mays L.)”. Semina: Ciências Agrárias, vol. 40, no. 6Supl2, Sept. 2019, pp. 3007-20, doi:10.5433/1679-0359.2019v40n6Supl2p3007.