0484-7903 0484-7903 S0484-79032019000400312 México México Mexico México México Mexico México México México México Mexico Mexico 00 12 2019 00 12 2019 42 4 312 314 1 2014 37 142-7 2 Pain & Policy Studies Group 3 2013 24 xi41-50 4 5 Universidad Nacional Autónoma de México 2009 6 2017 21 3-19 7 2017 7 207-15 8 2019 4 9 Sin autores 10 2019 11 Pain and policy study group 2011 12 2019 109 e1-e10 13 2019 109 26-7