Comparison and correction of element measurements using qualitative and quantitative X-ray fluorescence in lacustrine sediments: A case study of Lake HurlegAiying Cheng, Junqing Yu, Chunliang Gao and Lisha ZhangE3S Web Conf., 198 (2020) 03035DOI: https://doi.org/10.1051/e3sconf/202019803035