Masahiro Inuiguchi Fumiki Mizoshita SBM and Bipolar Models in Data Envelopment Analysis with Interval Data. 98-109 2008 MDAI http://dx.doi.org/10.1007/978-3-540-88269-5_10 conf/mdai/2008 db/conf/mdai/mdai2008.html#InuiguchiM08