R. Delen L. Clijmans J. Anthonis Herman Ramon A non-linear model to approximate the dynamics of a pulse width-modulated spray nozzle. 39-48 2004 65 Mathematics and Computers in Simulation 1-2 http://dx.doi.org/10.1016/j.matcom.2003.09.006 db/journals/mcs/mcs65.html#DelenCAR04