<http://www.vuetoo.com/vue1/Situationpagenews.asp?af=&sit=4540&z=&np=&tp=14>http://www.vuetoo.com/vue1/Situationpagenews.asp?af=&sit=4540&z=&np=&tp=14 and <http://www.pitt.edu/~super1/lecture/lec34601/index.htm>http://www.pitt.edu/~super1/lecture/lec34601/index.htm - public health lecture with slides www.peoplewho.org