J. M. Henriques, C. A. Barboza, E. L. Albuquerque, E. W. S. Caetano, V. N. Freire and J. A. P. Costa. First-principles calcula- tions of structural, electronic and optical prop-erties of ortho- rhombic CaPbO3. Journal of Physics D: Applied Phys-ics, 2008, 41(6): Article ID: 065405.