@article{journals/apal/EiterGG96,
  title = "Normal Forms for Second-Order Logic over Finite Structures, and Classification of NP Optimization Problems",
  author = "Thomas Eiter and Georg Gottlob and Yuri Gurevich",
  year = "1996",
  journal = "Ann. Pure Appl. Logic",
  number = "1-3",
  pages = "111-125",
  volume = "78",
}