Logic programming and nonmonotonic reasoning [Electronic resource] : 11th international conference, LPNMR 2011, Vancouver, Canada, May 16-19, 2011 : proceedings / ed. J. P. Delgrande, W. Faber. - Electronic text data. - Berlin ; Heidelberg : Springer, 2011. - (Lecture notes in computer science, ISSN 0302-9743 ; 6645). - ISBN 978-3-642-20895-9 : Б. ц.