@article{wei_frey_2021, title={Sensitivity of light duty vehicle tailpipe emission rates from simplified portable emission measurement systems to variation in engine volumetric efficiency}, DOI={10.1080/10962247.2021.1923586}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Wei, Tongchuan and Frey, H. Christopher}, year={2021}, month={Jun} }
 @article{wei_frey_2020, title={Evaluation of the Precision and Accuracy of Cycle-Average Light Duty Gasoline Vehicles Tailpipe Emission Rates Predicted by Modal Models}, ISBN={2169-4052}, DOI={10.1177/0361198120924006}, journal={TRANSPORTATION RESEARCH RECORD}, author={Wei, Tongchuan and Frey, H. Christopher}, year={2020} }
 @article{wei_frey_2020, title={Factors affecting variability in fossil-fueled transit bus emission rates}, volume={233}, ISBN={1873-2844}, DOI={10.1016/j.atmosenv.2020.117613}, journal={ATMOSPHERIC ENVIRONMENT}, author={Wei, Tongchuan and Frey, H. Christopher}, year={2020} }
 @article{yuan_frey_wei_rastogi_vandergriend_miller_mattison_2019, title={Comparison of real-world vehicle fuel use and tailpipe emissions for gasoline-ethanol fuel blends}, volume={249}, ISBN={1873-7153}, DOI={10.1016/j.fuel.2019.03.115}, journal={FUEL}, author={Yuan, Weichang and Frey, H. Christopher and Wei, Tongchuan and Rastogi, Nikhil and VanderGriend, Steven and Miller, David and Mattison, Lawrence}, year={2019}, pages={352–364} }