Klein, Wolfgang Language Acquisition Department, MPI for Psycholinguistics, Max Planck Society;
http://homepage.ruhr-uni-bochum.de/Bjoern.Rothstein/indexpp.html (Any fulltext)
Klein, W. (2010). The present perfect puzzle. Talk presented at the workshop Perfect Puzzles. Ruhr University Bochum, Germany. 2010-11-12.