Estimation of the Efficiency of Working Time Usage as a Factor of Sustainable Increase of Labor ProductivityI.V. Bogatyreva, L.A. Ilyukhina, M.V. Simonova and N.V. KozhukhovaSHS Web Conf., 62 (2019) 06002DOI: https://doi.org/10.1051/shsconf/20196206002