Media type: E-Article Title: Lecture Notes in Computer Science: Tableau Techniques for Querying Information Sources through Global Schemas Contributor: Grahne, Gösta; Mendelzon, Alberto O. imprint: Springer Berlin Heidelberg, 1999 Published in: Lecture Notes in Computer Science Language: Not determined DOI: 10.1007/3-540-49257-7_21 ISSN: 0302-9743 Origination: Footnote: