. 2014 Jan 30;2014:497642. doi: 10.1155/2014/497642
Copyright © 2014 Óscar González-Espasandín et al.
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 5.
2008–2012 evolution with % fuel cell UAVs trend.