@article{Zheng2015, author = "Shun-an Zheng and Xiangqun Zheng and Chun Chen", title = "{Variation of the percentage of metals in different fractions.}", year = "2015", month = "12", url = "https://plos.figshare.com/articles/figure/_Variation_of_the_percentage_of_metals_in_different_fractions_/208289", doi = "10.1371/journal.pone.0049664.g003" }