Gol Freixa, Jordi Maria2021-05-232021-05-232002Gac Sanit .2002; 16,(4): 3610213-9111http://hdl.handle.net/20.500.12105/12994spaVoRhttp://creativecommons.org/licenses/by-nc-nd/4.0/Attribution-NonCommercial-NoDerivatives 4.0 Internacional16436110.1016/S0213-9111(02)71937-7Gaceta Sanitariaopen access