- Correspondence to Dr Raquel Siqueira Barcelos, Programa de Pós-graduação em Epidemiologia, Faculdade de Medicina, Universidade Federal de Pelotas, Pelotas 96020-220, Brazil;
- Received October 19, 2017
- Revised December 9, 2017
- Accepted December 15, 2017
- First published February 26, 2018.
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