  The effects of planar hole concentration, p, and in-plane disorder, Zn (y),
on the DC resistivity, r(T), of sintered samples of
Y_{1-x}Ca_xBa_2(Cu_{1-y}Zn_y)_3O_{7-d} were investigated over a wide doping
range by changing both the oxygen deficiency (d) and Ca content (x). From the
r(T,p) data we extracted characteristic crossover temperatures on the
underdoped and overdoped sides, T* and T_m respectively, above which r(T) is
linear. We compare our results with a number of other polycrystalline, thin
film and single crystal cuprate superconductors and find similar behavior in
the p-dependence of T*(p), T_m(p), and the resistivity exponent, m(p), in fits
to r(T) = r_0 + aT^m on the overdoped side. Our findings point towards the
possible existence of a quantum critical point (QCP) at the doping p=0.19 +/-
0.01.
