Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W. & Harley, Robert A. Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks, article, February 2, 2009; (https://digital.library.unt.edu/ark:/67531/metadc926033/m1/1/: accessed November 17, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .