SakhoshkoМ., Kravchenko, M., Yatsenko, V. and Kolosok, I. 2019. Development of the leaf area and the productivity structure of the sunflower hybrids in the north-eastern Forest-Steppe of Ukraine. Bulletin of Sumy National Agrarian University. The series: Agronomy and Biology. 1-2(35-36) (Jul. 2019), 33-39. DOI:https://doi.org/10.32845/agrobio.2019.1-2.5.