Susano, R.M., Fialho, L.L. and de Quirós, J.F. 1993. A letter about the article: Drug surveillance: the concepts, objectives and methods (1992; 5: 595-602). Acta Médica Portuguesa. 6, 5 (May 1993), 230. DOI:https://doi.org/10.20344/amp.3076.