Identifying manifolds underlying group motion in Vicsek agents K. Gajamannage, S. Butail, M. Porfiri and E.M. Bollt Eur. Phys. J. Special Topics, 224 17-18 (2015) 3245-3256 Published online: 15 December 2015 DOI: 10.1140/epjst/e2015-50088-2