@article{Ballerini_2008_Ira,
author = {Ballerini, M. and Calbibbo, N. and Candelier, R. and Cavagna, A. and Cisbani, E. and Giardina, I. and Lecomte, V. and Orlandi, A. and Parisi, G. and Procaccini, A. and Viale, M. and Zdravkovic, V.},
title = {Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study},
journal = {PNAS},
year = {2008},
volume = {105},
number = {4},
month = {Jan},
}