@article{Kal.05,
    author = {M. Karpinski and I.I. Mandoiu and A. Olshevsky and A. Zelikovsky},
    title = {Improved Approximation Algorithms for the Quality of Service Multicast Tree Problem},
    journal = {Algorithmica},
    year = {2005},
    volume = {42},
    number = {2},
    pages = {109-120},
    url = {http://dx.doi.org/10.1007/s00453-004-1133-y},
    keywords = {lab},
    file = {Kal.05.pdf},
    confidential = {n}
}