@techreport{
    SiSc05,
    author = "{\v{S}}{\'{\i}}ma, Ji{\v{r}}{\'{\i}} and Schaeffer, Satu Elisa",
    title = "On the \np-Completeness of Some Graph Cluster Measures",
    pages = "9",
    address = "\url{http://arxiv.org/}",
    number = "cs.CC/0506100",
    month = "June",
    year = "2005",
    type = "Technical Report",
    institution = "arXiv.org e-Print archive"
}