%0 Journal Article %A Ayalew Getachew Mersha and Stephan Dempe %D 2009 %8 Array %T Direct search algorithm for bilevel programming problems %U http://www.springerlink.com/content/l15u262xr72367h7/?p=eef61c662003466ba9ef85f7db51bf69&pi=0 %J Computational Optimization and Applications