Multiband model for penetration depth in MgB2
  The results of first principles calculations of the electronic structure and the electron-phonon interaction in MgB2 are used to study theoretically the temperature dependence and anisotropy of the magnetic field penetration depth. The effects of impurity scattering are essential for a proper description of the experimental results. We compare our results with experimental data and we argue that the two-band model describes the data rather well. 
A. A. Golubov, A. Brinkman, O. V. Dolgov, J. Kortus, O. Jepsen