Ralf Russ Dana Sperling Frank Rometsch Peter Louis Applying Six Sigma in the Field of Software Engineering. 36-47 2008 IWSM/Metrikon/Mensura http://dx.doi.org/10.1007/978-3-540-89403-2_4 conf/iwsm/2008 db/conf/iwsm/iwsm2008.html#RussSRL08