Corral, J.
Parés, D.
García-Cuyás, F.
Revollo, B.
Videla, S.
Chamorro, A.
Piñol, M.
Clotet, B.
Sirera, G.
Article History
Received: 2 April 2019
Accepted: 16 July 2019
First Online: 23 July 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: As this was a systematic review of existing studies ethical approval was not required.
: For this type of study formal consent is not required.