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References:
[1] Castleton, C. W. M., A. Höglund, and Susanne Mirbt. "Density functional theory calculations of defect energies using supercells." Modelling and Simulation in Materials Science and Engineering 17.8 (2009): 084003. http://iopscience.iop.org/0965-0393/17/8/084003
[2] Shim, Jihye, et al. "Density-functional calculations of defect formation energies using supercell methods: Defects in diamond." Physical Review B 71.3 (2005): 035206. http://journals.aps.org/prb/pdf/10.1103/PhysRevB.71.035206