Luca Becchetti Stefano Leonardi S. Muthukrishnan Average stretch without migration. 80-95 2004 68 J. Comput. Syst. Sci. 1 http://dx.doi.org/10.1016/j.jcss.2003.06.001 db/journals/jcss/jcss68.html#BecchettiLM04