On the quantization of Burgers vector and gravitational energy in the space-time of a conical defectF. L. Carneiro, S. C. Ulhoa, J. F. da Rocha-Neto and J. W. MalufEur. Phys. J. C, 80 3 (2020) 226DOI: https://doi.org/10.1140/epjc/s10052-020-7772-6