About this article
Published Online: Dec 31, 2018
Page range: 2 - 21
DOI: https://doi.org/10.2478/disp-1997-0001
© 2019 Fernando Ferreira, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.
Fernando Ferreira
Universidade de Lisbon,Lisbon, Portugal