@article{MathematicaBalkanica, author = "C. Papagianni and Pappas, Christos A. and Nikos Lefkaditis and Venieris, Iakovos S.", journal = "Mathematica Balkanica", month = "May", pages = "303-324", title = "{A} {P}article {S}warm {O}ptimization {A}pproach to the {M}ulti {L}evel {C}apacitated {M}inimum {S}panning {T}ree {P}roblem", volume = "23", year = "2009", }