Cvetkovic, D. States of consciousness [Electronic resource] : experimental insights into meditation, waking, sleep and dreams / D. Cvetkovic, I. Cosic. - Electronic text data. - Berlin ; Heidelberg : Springer, 2011. - (The frontiers collection, ISSN 1612-3018). - ISBN 978-3-642-18047-7 : Б. ц.