Engel, Christoph Max Planck Institute for Research on Collective Goods, Max Planck Society;
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2046505 (Any fulltext)
http://www.coll.mpg.de/pdf_dat/2012_10online.pdf (Preprint)
Buch, C. M., & Engel, C. (2012). Effort and Redistribution: Better Cousins Than One Might Have Thought.