Message Classification in the Call Center Stephan Busemann author Sven Schmeier author Roman G Arens author 2000-04 text Sixth Applied Natural Language Processing Conference Association for Computational Linguistics Seattle, Washington, USA conference publication busemann-etal-2000-message 10.3115/974147.974169 https://aclanthology.org/A00-1022/ 2000-04 158 165