Sousa, A S
Guerra, R S
Fonseca, I
Pichel, F
Ferreira, S
Amaral, T F
Article History
Received: 6 October 2015
Revised: 14 March 2016
Accepted: 10 April 2016
First Online: 11 May 2016
Competing interests
: The authors declare no conflict of interest.