Artificial intelligence in education [Electronic resource] : 15th international conference, AIED 2011, Auckland, New Zealand, June 28 – July 2011 / eds. G. Biswas [et al.]. - Electronic text data. - Berlin ; Heidelberg : Springer, 2011. - (Lecture notes in computer science, ISSN 0302-9743 ; 6738). - ISBN 978-3-642-21869-9 : Б. ц.