Discovery of a new quadruply lensed QSO: HS 0810+2554 – A brighter twin to PG 1115+080 D. Reimers, H.-J. Hagen, R. Baade, S. Lopez and D. Tytler A&A, 382 3 (2002) L26-L28 Published online: 15 February 2002 DOI: 10.1051/0004-6361:20011798