Funding for this research was provided by:
Ministerio de Economía, Industria y Competitividad, Gobierno de España (MTM2017-85054-C2-2-P, MTM2017-85054-C2-2-P)
ETSII-UNED (2019-MAT11)
ETSII-UNED
Article History
Received: 3 September 2018
Revised: 27 February 2019
First Online: 6 June 2019