Alexander V. Smirnov Mikhail Pashkin Nikolai Chilov Tatiana Levashova Andrew Krizhanovsky Alexey Kashevnik Ontology-Based Users & Requests Clustering in Customer Service Management System http://arxiv.org/abs/cs/0501077 2005 CoRR abs/cs/0501077 db/journals/corr/corr0501.html#abs-cs-0501077 informal publication