Joel da Silva Valéria Cesário Times Ana Carolina Salgado Clenúbio Souza Robson do Nascimento Fidalgo Anjolina Grisi de Oliveira A set of aggregation functions for spatial measures. 25-32 2008 DOLAP http://doi.acm.org/10.1145/1458432.1458438 conf/dolap/2008 db/conf/dolap/dolap2008.html#SilvaTSSFO08