@Article{ricci2011,
  author =          {Ricci, D.},
  author =          {..,},
  author =          {Zimmer, F.},
  author =          {Zub, M.},
  author =          {Surdej, J.},
  title =           {Flux and color variations of the quadruply imaged quasar HE 0435-1223},
  journal =         {Astron Astrophys},
  year =            {2011},
  volume =          {528},
  pages =           {A42},
  month =           {April},
  note =            {Provided by the SAO/NASA Astrophysics Data System}}