- Ulrich Lichtenthaler, The role of corporate technology strategy and patent portfolios in low-, medium- and high-technology firms, Res. Policy, 38 (2009) 559–569, http://dx.doi.org/10.1016/j.respol.2008.10.009 (Retraction notice)
- Ulrich Lichtenthaler, Determinants of proactive and reactive technology licensing: A contingency perspective, Res. Policy, 39 (2010) 55–66, http://dx.doi.org/10.1016/j.respol.2009.11.011 (Retraction notice)
- Ulrich Lichtenthaler and Holger Ernst, Technology licensing strategies: the interaction of process and content characteristics, Strategic Organization, Vol 7(2): 183–221, DOI: 10.1177/1476127009102672
One paper was retracted because it was apparently a multiple publication (self-plagiarism), the others for statistical issues. Germany has no national policy on retractions, and even though some universities have ethical codices, there is often no clear road to follow when something like this comes up. With the amount of ethical problems being uncovered in Germany recently, one would think that there would be a national committee investigating. If there is, I am unaware of it.
Update August 16, 2012: Retractionwatch has documented a fourth retraction by Lichtenthaler, this time from Strategic Management Journal.