David Binkley Sebastian Danicic Tibor Gyimóthy Mark Harman Ákos Kiss Bogdan Korel 23-41 2006 360 Theor. Comput. Sci. 1-3 http://dx.doi.org/10.1016/j.tcs.2006.01.012 db/journals/tcs/tcs360.html#BinkleyDGHKK06