Andwari, Amin Mahmoudzadeh, et al. “Effect of Internal and External EGR on Cyclic Variability and Emissions of a Spark Ignition Two-Stroke Cycle Gasoline Engine”. Journal of Mechanical Engineering and Sciences, vol. 11, no. 4, Dec. 2017, pp. 3004-1, doi:10.15282/jmes.11.4.2017.4.0270.