Omidvarborna; et al. Characterization of particulate matter emitted from transit buses fueled with B20 in idle modes. Journal of Environmental Chemical Engineering. 2014, 2 (4): 2335–2342. doi:10.1016/j.jece.2014.09.020.
Caiazzo, Fabio; Ashok, Akshay; Waitz, Ian A.; Yim, Steve H.L.; Barrett, Steven R.H. Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005. Atmospheric Environment. November 2013, 79: 198–208. Bibcode:2013AtmEn..79..198C. doi:10.1016/j.atmosenv.2013.05.081.