Herschel-PACS far-infrared photometry of two z > 4 quasars C. Leipski, K. Meisenheimer, U. Klaas, F. Walter, M. Nielbock, O. Krause, H. Dannerbauer, F. Bertoldi, M.-A. Besel, G. de Rosa et al. (7 more) A&A, 518 (2010) L34 Published online: 16 July 2010 DOI: 10.1051/0004-6361/201014718