Published Online: Dec 31, 2018
Page range: 43 - 47
DOI: https://doi.org/10.2478/disp-1996-0006
© 2019 J. Félix Costa, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.
J. Félix Costa
Centro de Ciências da Complexidade, Faculdade de Ciências de Lisboa, Rua Ernesto de Vasconcelos,Lisboa, Portugal