Seigo Karakawa Ehab Morsy Hiroshi Nagamochi Minmax Tree Cover in the Euclidean Space. 202-213 2009 WALCOM http://dx.doi.org/10.1007/978-3-642-00202-1_18 conf/walcom/2009 db/conf/walcom/walcom2009.html#KarakawaMN09