Sunflower productivity and gross oil production on the grey forest soil of the republic of Tatarstan under the use of growth regulatorsVladimir P. Vladimirov, Evgeniy M. Chugunov, Antonina A. Mostyakova and Arsen A. IlgamovBIO Web Conf., 17 (2020) 00020DOI: https://doi.org/10.1051/bioconf/20201700020