Eiter, T., Gottlob, G., & Gurevich, Y. (1996). Normal Forms for Second−Order Logic over Finite Structures‚ and Classification of NP Optimization Problems.

Eiter, T., G. Gottlob, and Y. Gurevich. Normal Forms for Second−Order Logic over Finite Structures‚ and Classification of NP Optimization Problems. 1996.

Eiter, T., et al. Normal Forms for Second−Order Logic over Finite Structures‚ and Classification of NP Optimization Problems. 1996.