Anding Li, Guojun Cai, Limin Zhang,Chunyan Guo. “Variations of Nitrogen-15 Natural Abundance in Three Plants and Soils from the Typical Karst Peak Cluster Depression, South Guizhou, China”. Design Engineering (September 29, 2020): 861 - 871. Accessed May 18, 2024. http://www.thedesignengineering.com/index.php/DE/article/view/822.