1. Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison-Wesley, Boston (1995)
2. Baget, J.-F., Mugnier, M.-L., Rudolph, S., Thomazo, M.: Walking the complexity lines for generalized guarded existential rules. In: IJCAI, pp. 712–717 (2011)
3. Barceló, P., Gottlob, G., Pieris, A.: Semantic acyclicity under constraints. In: PODS (2016)
4. Barceló, P., Libkin, L., Romero, M.: Efficient approximations of conjunctive queries. SIAM J. Comput. 43(3), 1085–1130 (2014)
5. Barceló, P., Romero, M., Vardi, M.Y.: Semantic acyclicity on graph databases. In: PODS, pp. 237–248 (2013)