No evidence for dust extinction in GRB 050904 at z ~ 6.3T. Zafar, D. J. Watson, D. Malesani, P. M. Vreeswijk, J. P. U. Fynbo, J. Hjorth, A. J. Levan and M. J. MichałowskiA&A, 515 (2010) A94DOI: https://doi.org/10.1051/0004-6361/200913795
