due to adhesion forces 126]. This fact is confirmed in Fig. 3, where we plot the coefficient periment between two sheets of a standard a function of tribology ex paper, as kinetic friction obtained from the applied normal load(squares Let us now compare this result with the interleaved-book case. As explained above, our model is based on the AC laws and considers single average u for each experiment, that is constant irrespective of the load. This hypothesis is equivalent to taking a coarse-grained approach, even though the load increases towards the centre of the books and at tmall d. The previous assumption is sufficient to describe the data, evidenced by the fit in the inset of Fig. 3. Then we define through AC laws an effective load per page, N T/(4MH), which would correspond to the load ap- plied on each page if the 2MI sheets were o). Note that, by defining the microscopic load T/(2u), Eq. (3) also provides the amplification gain N/N in normal load. The average traction force(7) of a given experiment is calculated over the range applicability of the theory, and used to obtain the av erage effective load per page(N). The result u(W)) is e Fig. 3(circles), with the ranges of applicabil shown in indicated by the grey single of be used to adequately describe each T(d) experiment with the theory, even though the load varied over the indicat range. The consistency