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Kikot, Stanislav and Kontchakov, Roman and Podolskii, V. and Zakharyaschev, Michael (2012) Exponential lower bounds and separation for query rewriting. In: Czumaj, A. and Mehlhorn, K. and Pitts, A. and Wattenhofer, R. (eds.) Automata, Languages, and Programming. Lecture Notes in Computer Science 7392 7392. Berlin, Germany: Springer, pp. 263-274. ISBN 9783642315848.