1. California Air Resources Board
. “Facts about the Low NOX Heavy-Duty Omnibus Regulation,” 2020. https://ww2.arb.ca.gov/sites/default/files/classic//msprog/hdlownox/files/HD_NOx_Omnibus_Fact_Sheet.pdf.
2. Environmental Protection Agency
, “Advanced Notice of Proposed Rule Making,” Federal Register 85, no. 13 (January 21, 2020): 3306-3330. https://www.govinfo.gov/content/pkg/FR-2020-01-21/pdf/2020-00542.pdf.
3. “ECFR - Code of Federal Regulations.” Electronic Code of Federal Regulations (eCFR). Office of Federal Register. Accessed November 15, 2020. https://www.ecfr.gov/cgi-bin/text-idx?tpl=/ecfrbrowse/Title40/40cfr1065_main_02.tpl.
4. “ECFR - Code of Federal Regulations.” Electronic Code of Federal Regulations (eCFR). Office of Federal Register. Accessed November 15, 2020. https://www.ecfr.gov/cgi-bin/text-idx?tpl=/ecfrbrowse/Title40/40cfr1036_main_02.tpl.
5. EPA
, “Nonroad Diesel Engines”, U.S. Environmental Protection Agency; website, viewed 4-Oct-2021, 2013. http://www.epa.gov/otaq/nonroad-diesel.htm.