Thermal production of positronium in porous alumina F. Moia, R. Ferragut, A. Dupasquier, M.G. Giammarchi and G.Q. Ding Eur. Phys. J. D, 66 5 (2012) 124 Published online: 17 May 2012 DOI: 10.1140/epjd/e2012-20637-0