Lomax, A., C. Satriano and M. Vassallo (2012), Automatic picker developments and optimization: FilterPicker - a robust, broadband picker for real-time seismic monitoring and earthquake early-warning, Seism. Res. Lett. , 83, 531-540, doi: 10.1785/gssrl.83.3.531. (PDF).
In Lomax et al. (2012) there is an error in eq. (5). The correct form of the equation is