Cluster persistence: A discriminating probe of soap froth dynamics W. Y. Tam, A. D. Rutenberg, B. P. Vollmayr-Lee and K. Y. Szeto Europhys. Lett., 51 2 (2000) 223-229 Published online: 01 September 2002 DOI: 10.1209/epl/i2000-00535-4