Brusa, M. High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Daddi, E., Renzini, A., Pirzkal, N., Cimatti, A., Malhotra, S., Stiavelli, M., et al. (2005). Passively evolving early-type galaxies at 1.4 <~ z <~ 2.5 in the Hubble ultra deep field. The Astrophysical Journal, 626(2), 680-697. doi:10.1086/430104.