One of these two articles.

• Eisenhoffer, G. T., Loftus, P. D., Yoshigi, M., Otsuna, H., Chien, C.-B., Morcos, P. A., & Rosenblatt, J. (2012). Crowding induces live cell extrusion to maintain homeostatic cell numbers in epithelia. Nature, 484(7395), 546–9. doi:10.1038/nature10999 Link

• Petrie, R. J., Gavara, N., Chadwick, R. S., & Yamada, K. M. (2012). Nonpolarized signaling reveals two distinct modes of 3D cell migration. The Journal of cell biology, 197(3), 439–55. doi:10.1083/jcb.201201124 Link

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