Analysis of the correlation between the red EDGE vegetation indices and the gross primary productivity of winter wheat crop according to gas and spectrometric measurements in Barys... von Lyalko, Vadim, Sakhatskyi, Oleksii, Zholobak, Galina, Sybirtseva, Oksana, Dugin, Stanislav, Vakolyuk, Mariana, Khalaim, Oleksandra