Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., et al. (2015). Study of the rare B0s and B0 decays into the π+π-μ+μ- final state. Physics Letters B, 743, 46-55. doi:10.1016/j.physletb.2015.02.010.