Holding, J. M.
Duarte, C. M.
Sanz-Martín, M.
Mesa, E.
Arrieta, J. M.
Chierici, M.
Hendriks, I. E.
García-Corral, L. S.
Regaudie-de-Gioux, A.
Delgado, A.
Reigstad, M.
Wassmann, P.
Agustí, S.
Article History
Received: 12 December 2014
Accepted: 23 July 2015
First Online: 31 August 2015
Change Date: 8 September 2015
Change Type: Corrigendum
Change Details: In the version of this Letter originally published online, the following should have been included in the Acknowledgements: 'M.S.-M. was funded by Fundación 'La Caixa' PhD grants (Spain).' This error has been corrected in all versions of the Letter.
Competing interests
: The authors declare no competing financial interests.