Berry’s phase for a spin 1/2 particle in the presence of topological defects Josevi de S. Carvalho, E. Passos, Claudio Furtado and Fernando Moraes Eur. Phys. J. C, 57 4 (2008) 817-822 Published online: 30 August 2008 DOI: 10.1140/epjc/s10052-008-0696-1