Spitzer Space Telescope observations of the nucleus of comet 67P/Churyumov-GerasimenkoP. L. Lamy, I. Toth, O. Groussin, L. Jorda, M. S. Kelley and J. A. StansberryA&A, 489 2 (2008) 777-785DOI: https://doi.org/10.1051/0004-6361:200809514