HE 0435-1223: A wide separation quadruple QSO and gravitational lens L. Wisotzki, P. L. Schechter, H. V. Bradt, J. Heinmüller and D. Reimers A&A, 395 1 (2002) 17-23 Published online: 29 October 2002 DOI: 10.1051/0004-6361:20021213