Erosion of cfc, pyrolytic and boronated graphite under short pulsed laser irradiation / G.J. Kraaij, J. Bakker, R.C.L. van der StadEvaluation of metallic samples irradiated in JEBIS in 1990 / G.J. KraaijWaterstof bij Ecomare : opties voor inzet / Gerard KraaijConversion of excess wind energy into hydrogen for fuel cell applications : a system analysis within the context of the Dutch energy system / Gerard Kraaij, Marcel Weeda