G.W.~Klau, I.~Ljubić, A.~Moser, P.~Mutzel, P.~Neuner, U.~Pferschy, G.~Raidl, R.
Weiskircher. Combining a Memetic Algorithm with Integer Programming to Solve the Prize-Collecting Steiner Tree Problem. Genetic and Evolutionary Computation – GECCO 2004 (K.Deb and others), volume 3102 of LNCS, pages 1304-1315, 2004, Springer.