Thongkum, W., J. Wibuloutai, and S. Thitisutthi. “Benzene and 1, 3 Butadiene Concentration and Its Potential Health Impact in Chiang Mai, Thailand”. European Journal of Sustainable Development, vol. 6, no. 2, June 2017, p. 187, doi:10.14207/ejsd.2017.v6n2p187.