Algorithm for Finding $k$-Vertex Out-trees and its Application to $k$-Internal Out-branching Problem

Nathann Cohen Fedor V. Fomin Gregory Gutin Eun Jung Kim Saket Saurabh Anders Yeo Algorithm for Finding $k$-Vertex Out-trees and its Application to $k$-Internal Out-branching Problem http://arxiv.org/abs/0903.0938 2009 CoRR abs/0903.0938 db/journals/corr/corr0903.html#abs-0903-0938 informal publication