Bertel, E. Surface Science (OP), Max Planck Institute for Plasma Physics, Max Planck Society;
Bertel, E. (1997). Electronic surface states and the hydrogen dissociation barrier. Physica Status Solidi A-Applications and Materials Science, 159(1), 235-242. doi:10.1002/1521-396X(199701)159:1<235:AID-PSSA235>3.0.CO;2-1.