Hans-Werner Sinn, Erkki Koskela, Ronnie Schoeb
in: H. Chernick, Hrsg., Proceedings of the 91st Annual Conference on Taxation, National Tax Association: Washington D.C. 1999, S. 52-56; CESifo Working Paper Nr. 176, 1998; NBER Working Paper Nr. 6922, Februar 1999.