Slawomir Zadrozny, Janusz Kacprzyk. Bipolar Queries: A Way to Deal with Mandatory and Optional Conditions in Database Querying. In Janusz Kacprzyk, Frederick E. Petry, Adnan Yazici, editors, Uncertainty Approaches for Spatial Data Modeling and Processing: A Decision Support Perspective. Volume 271 of Studies in Computational Intelligence, pages 117-132, Springer, 2010. [doi]
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