Mooij Rule and Weak Localization
  It has been shown that the observed correlation between the resistivity $\rho$ of high-resistive metallic alloys and the sign of the temperature derivative $d\rho/dT$ can be explained by taking into account the weak localization. This correlation is known as Mooij rule: the derivative $d\rho/dT$ is negative for alloys with resistivity in the range of $300\div150\,\mu\Omega\cdot$cm, which corresponds to the electron mean free path about the interatomic distance; however, this derivative is positive for alloys with lower resistivity. 
V.F. Gantmakher
cond-mat.str-el cond-mat.other