Analysis of patent sources in the field of environmental monitoring of objectsAlexandra Petryaeva, Marina Bolsunovskaya, Svetlana Shirokova, Aleksandr Leksashov, Andrey Zhukov, Aleksander Kuptsov and Dmitry KazakovE3S Web Conf., 284 (2021) 01005DOI: https://doi.org/10.1051/e3sconf/202128401005