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title={Hypergroups and $n$-ary relations},
author={S. some},
title={Soft Computing-Based Recognition of Musical Sounds},
publisher={European Journal of Combinatorics},
year={2009},
author={H. Cristea and  M. Stefaneseu},
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@incollection{12,
year={1998},
title={Rough Sets in Knowledge Discovery 2},
volume={19},
series={Studies in Fuzziness and Soft Computing},
editor={ Lech, P. and  Andrzej, S.},
title={Soft Computing-Based Recognition of Musical Sounds},
publisher={Physica-Verlag HD},
author={K. Bozena},
pages={193-213},
}