Left panel: Normalized signal from various observables (the innermost ring of VZERO-A and VZERO-C and two rapidity intervals of $\dNdeta$) versus the normalized charged-particle density averaged over $-1 < \eta < 0$. Left panel: fit with the linear function from Eq. \ref{eq:Npartfit}. Right panel: fit with the power-law function from Eq. \ref{eq:Plawfit}. Only data from p-Pb collisions are shown