Geochemistry of the rare earth elements in the sparkling groundwaters of the Caucasus ridge, RussiaEvgenia Chirkova, Ekaterina Baranovskaya, Natalia Kharitonova, Vasily Lavrushin, Georgy Chelnokov and Ivan BraginE3S Web Conf., 98 (2019) 01009DOI: https://doi.org/10.1051/e3sconf/20199801009