Zhou, Qingtao, Charles T. Driscoll, Stephen E. Moore, Matt A. Kulp, James R. Renfro, John S. Schwartz, Meijun Cai, and Jason A. Lynch. "Developing Critical Loads of Nitrate and Sulfate Deposition to Watersheds of the Great Smoky Mountains National Park, USA." Water, Air, & Soil Pollution 226, no. 8 (2015).