Commentary on “T.G. Ritto, M.R. Escalante, Rubens Sampaio, M.B. Rosales, Drill-string horizontal dynamics with uncertainty on the frictional force, Journal of Sound and Vibration 332 (2013) 145–153”

Abstract The goal of this article is to clarify some points of the formulation presented in the “T.G. Ritto, M.R. Escalante, Rubens Sampaio, M.B. Rosales, Drill-string horizontal dynamics with uncertainty on the frictional force, Journal of Sound and Vibration 332 (2013) 145–153”.