In & out zooming on time-aware user/tag clusters

E. Giannakidou, V. Koutsonikola, A. Vakali and I. Kompatsiaris, "In & out zooming on time-aware user/tag clusters", in Journal of Intelligent Information Systems, Vol 38, Issue 3(2012) pages 685-708, DOI: 10.1007/s10844-011-0173-4