@article{Gay:29713,
      title = {Toward a Sustainability Indicator for Buildings},
      author = {Gay, J.-B. and Homem de Freitas, J. and Ospelt, Ch. and  Rittmeyer, P. and Sindayigaya, O.},
      journal = {2ème Conférence internationale - Bâtiment et  environnement - Paris},
      year = {1997},
      url = {http://infoscience.epfl.ch/record/29713},
}