@misc {IOPORT.70900111,
    author       = {Powers, Simon T. and Penn, Alexandra S. and Watson, Richard A.},
    title        = {Individual selection for cooperative group formation},
    howpublished = {ECAL, 585-594 (2007).},
    year         = {2007},
    doi          = {10.1007/978-3-540-74913-4_59},
    identifier   = {70900111},
}