Vortices formation by oscillatory excitation of a BEC - Henn, Emanuel Alves de Lima; Seman, J. A.; Ramos, E. R. F.; Caracanhas, M.; Olimpio, E. P.; Castilho, Patricia Christina Marques; Roati, G.; Magalhães, Daniel Varela; Magalhães, Kílvia Mayre Farias; Bagnato, Vanderlei Salvador (International Conference on Atomic Physics - ICAP, 2008)