1. Beechie B, Ohl G, Yip J, Prucka M. Engine friction characterization. US Patent 6188951 B1, 2001.
2. Interpolation and numerical differentiation for observer design;Diop,1994
3. Sandoval D, Heywood J. An improved friction model for spark-ignition engines, SAE Paper, 2003-01-0725
4. Variable structure control of engine idle speed with estimation of unmeasurable disturbances;Stotsky;J Dyn Sys Mes Control,2002
5. Recursive spline interpolation method for real-time engine control applications;Stotsky;Control Eng Pract,2004