1. Ajtai, M.: ${\Sigma_1^1}$ -formulae on finite structures. Ann. Pure Applied Logic 24, 1–48 (1983)
2. Alon, N., Spencer, J.: The Probabilistic Method. John Wiley & Sons, Inc, Chichester (2000)
3. Baker, T., Gill, J., Solovay, R.: Relativizatons of the P =? NP question. SIAM J. Comput. 4(4), 431–442 (1975)
4. Balcázar, J., Díaz, J., Gabarró, J.: Structural Complexity I & II. Springer, Heidelberg (1989-1990)
5. Cai, J.-Y.: With probability one, a random oracle separates PSPACE from the polynomial-time hierarchy. In: Proc. 18th ACM Sympos. on Theory of Comput (STOC 1989), pp. 21–29 (1986); The final version appeared. J. Comp. Syst. Sci. 38(1), 68–85 (1989)