Grigoryan, Arsen T. “OPTIMIZATION PROBLEMS OF WINTER WHEAT CROP DАTES IN ALTITUDE ZONES IN THE REPUBLIC OF ARMENIA”. Proceedings of the YSU C: Geological and Geographical Sciences, vol. 44, no. 1 (221), Mar. 2010, pp. 40-45, doi:10.46991/PYSU:C/2010.44.1.040.