Gabriella Casalino, Nicoletta Del Buono, Corrado Mencar, Subtractive clustering for seeding non-negative matrix factorizations, Information Sciences, Volume 257, 1 February 2014, Pages 369-387, ISSN 0020-0255, http://dx.doi.org/10.1016/j.ins.2013.05.038. (http://www.sciencedirect.com/science/article/pii/S0020025513004349) This code is kindly provided by the authors for research purposes. For questions or comments please send an e-mail to Gabriella Casalino (gabriella.casalino@uniba.it)