A. Q. Guo, R. A. Briere, V. Bytev et al.|Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields|2010
C. Geng, M. N. Achasov, Diego Alberto et al.|Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields|2011