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(a) Rescaled number of stations at distance r from the barycentre as a function of the rescaled variable r/rC where rC is the size of the core defined as N(r = rC) = NC (shown here in log–log). The dotted line represents a power law ∼r2 and serves as a guide to the eye. (b) The case of Moscow where the two regimes (r < rC and r > rC) with their different exponents are visible (the dotted lines serve here as a guide to the eye). (Online version in colour.)
