@ARTICLE{Kaczorek_T._Positivity_2015, author={Kaczorek, T.}, volume={63}, number={No 2}, journal={Bulletin of the Polish Academy of Sciences Technical Sciences}, pages={561-565}, howpublished={online}, year={2015}, title={Positivity of a class of fractional descriptor continuous-time nonlinear systems}, URL={http://journals.pan.pl/Content/84269/PDF/28_paper.pdf}, doi={10.1515/bpasts-2015-0065}, }