@article{Goldoni:200939,
  author = "Goldoni, Otavio  and  da Silva, Maria de Fátima Alves",
  title = "{Energy conditions for electromagnetic field in presence of cosmological constant}",
  doi = "10.22323/1.081.0072",
  journal = "PoS",
  year = 2009,
  volume = "ISFTG",
  pages = "072"
}