Gianluca De Marco Luisa Gargano Evangelos Kranakis Danny Krizanc Andrzej Pelc Ugo Vaccaro 315-326 2006 355 Theor. Comput. Sci. 3 http://dx.doi.org/10.1016/j.tcs.2005.12.016 db/journals/tcs/tcs355.html#MarcoGKKPV06