Науменко, Н. И., М. Н. Загуменов, И. В. Ермолаев, and А. Г. Меньшиков. “EXPERIENCE OF ORGANIZING AN ENVIRONMENTAL TRAIL IN THE ALNASH DISTRICT OF THE UDMURT REPUBLIC”. Actual Problems of Pedagogy and Psychology. Scientific Peer-Reviewed Electronic Journal (online Edition) 16+, vol. 1, no. 3, Dec. 2020, pp. 26-37, http://pedpsy.ru/index.php/ped/article/view/20.