S. Diana, B. Lorio, V. Giglio and G. Police, “The Effect of Valve Lift Shape and Timing on Air Motion and Mixture Formation of DISI Engines Adopting Different VVA Actuators,” SAE Paper No. 2001-01-3553, 2001.
 G. Fontana and E. Galloni, “Variable Valve Timing for Fuel Economy Improvement in a Small Spark-Ignition Engine,” Applied Energy, Vol. 39, No. 86, 2009, pp. 96-105. doi:10.1016/j.apenergy.2008.04.009
 Y. Ping, X. Zhang, Y. Dong, G. Zhu and Q. Wang, “Study on Performance Improvement of Vehicle Engine by Using Variable Cam Timing,” Chinese Internal Combustion Engine Engineering, Vol. 29, No. 6, 2008, pp. 20-23.
 H. S. Yan, M. C. Tsai and M. H. Hsu, “An Experimental Study of the Effects of Cam Speed on Cam-Follower Systems,” Mechanism and Machine Theory, Vol. 31, No. 4, 1996, pp. 397-412. doi:10.1016/0094-114X(95)00087-F
 F. Bozza, A. Gimelli, A. Senatore and A. Caraceni, “A Theoretical Comparison of Various VVA Systemsfor Performance and Emission Improvement of SI Engines,” SAE Technical Paper No. 2001-01-0670, 2001.
 H. S. Yan and W. R. Chen, “On the Output Motion Characteristics of Variable Speed Input Servo-Controlled SliderCrank Mechanisms,” Mechanism and Machine Theory, Vol. 35, No. 4, 2000, pp. 541-561. doi:10.1016/S0094-114X(99)00023-3
 H. Hong, G. B. Parvate-Patil and B. Gordon, “Review and Analysis of Variable Valve Timing Strategies-Eight Ways to Approach,” Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Vol. 218, No. 10, 2004, pp. 1179-1200. doi:10.1177/095440700421801013