Krists Boitmanis Karlis Freivalds Peteris Ledins Rudolfs Opmanis Fast and Simple Approximation of the Diameter and Radius of a Graph. 98-108 2006 conf/wea/2006 WEA http://dx.doi.org/10.1007/11764298_9 db/conf/wea/wea2006.html#BoitmanisFLO06