Discovery of a new quadruply lensed QSO: HS 0810+2554 – A brighter twin to PG 1115+080D. Reimers, H.-J. Hagen, R. Baade, S. Lopez and D. TytlerA&A, 382 3 (2002) L26-L28DOI: https://doi.org/10.1051/0004-6361:20011798
