1. Serge Abiteboul , Richard Hull , and Victor Vianu . 1995. Foundations of Databases: The Logical Level 1 st ed.). Addison-Wesley Longman Publishing Co., Inc. , USA. Serge Abiteboul, Richard Hull, and Victor Vianu. 1995. Foundations of Databases: The Logical Level 1st ed.). Addison-Wesley Longman Publishing Co., Inc., USA.
2. Spark SQL
3. Guillaume Bagan , Arnaud Durand , and Etienne Grandjean . 2007. On Acyclic Conjunctive Queries and Constant Delay Enumeration (CSL'07/EACSL'07) . Springer-Verlag , 208--222. Guillaume Bagan, Arnaud Durand, and Etienne Grandjean. 2007. On Acyclic Conjunctive Queries and Constant Delay Enumeration (CSL'07/EACSL'07). Springer-Verlag, 208--222.
4. On the Enumeration Complexity of Unions of Conjunctive Queries