Funding for this research was provided by:
Spanish project (S2009TIC-1465 PROMETIDOS)
EU Project FP7 (256980 NESSoS)
Madrid Regional project (S2009TIC-1465 PROMETIDOS)
ANII-Fondo Clemente Estable (PR-FCE-2009-1-2568 VirtualCert)
Article History
Received: 13 December 2016
Accepted: 14 November 2017
First Online: 30 November 2017