Femtosecond spin dynamics of ferromagnetic thin films and nanodots probed by spin-polarized photoemission electron microscopy, Heitkamp, B., Kronast, F., Heyne, L., Dürr, H.A., Eberhardt, W., Landis, S., Rodmacq, B., Journal of Physics D: Applied Physics, 41, 164002 (2008)