Improvement of ecological tourism on the principles of sustainable economic developmentUtegaly Shedenov, Oleg Litvishko, Beket Kazbekov, Maiya Suyunchaliyeva and Kairzhan KazbekovaE3S Web Conf., 135 (2019) 04047DOI: https://doi.org/10.1051/e3sconf/201913504047