R. Beaglehole et al., Epidemiologia di base, 1993, pag. 19 ([Internet, 2020-12-03](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi_2eiLxLHtAhWNMewKHfvJCcoQFjABegQIBRAC&url=https%3A%2F%2Fapps.who.int%2Firis%2Fbitstream%2Fhandle%2F10665%2F43541%2F887266031_ita.pdf%3Fsequence%3D6%26isAllowed%3Dy&usg=AOvVaw0mbu1lRBw050JIPFmtG488))