Przemyslaw Kazienko Piotr Bródka Dymitr Ruta The Influence of Customer Churn and Acquisition on Value Dynamics of Social Neighbourhoods. 491-500 2009 WSKS (1) http://dx.doi.org/10.1007/978-3-642-04754-1_50 conf/wsks/2009-1 db/conf/wsks/wsks2009-1.html#KazienkoBR09