@article{WisotzkiBeckerChristensenetal.2003,
  author    = {Lutz Wisotzki and Thomas Becker and Lise Bech Christensen and Andreas Helms and Knud Jahnke and A. Kelz and Martin M. Roth and Sebastian F. Sanchez},
  title     = {Integral-field spectrophotometry of the quadruple QSO HE 0435-1223 : Evidence for microlensing},
  year      = {2003},
}