Roberto Pieraccini David Suendermann Krishna Dayanidhi Jackson Liscombe Are We There Yet? Research in Commercial Spoken Dialog Systems. 3-13 2009 TSD http://dx.doi.org/10.1007/978-3-642-04208-9_3 conf/tsd/2009 db/conf/tsd/tsd2009.html#PieracciniSDL09