Prologue

License

In order to support the global exchange of knowledge, the journal Físca de la Tierra is allowing unrestricted access to its content as from its publication in this electronic edition, and as such it is an open-access journal. The originals published in this journal are the property of the Complutense University of Madrid and any reproduction thereof in full or in part must cite the source. All content is distributed under a Creative Commons Attribution 4.0 use and distribution licence (CC BY 4.0). This circumstance must be expressly stated in these terms where necessary. You can view the summary and the complete legal text of the licence.