Analytical treatment of synchronization of spin-torque oscillators by microwave magnetic fields R. Bonin, G. Bertotti, C. Serpico, I. D. Mayergoyz and M. d'Aquino Eur. Phys. J. B, 68 2 (2009) 221-231 Published online: 14 March 2009 DOI: 10.1140/epjb/e2009-00091-9