N.H.D.

http://www.mcatmaster.com/medicine&war/yellowfever.htm

http://www.geocities.com/bobarnebeck/history.html

http://www.pbs.org/wgbh/aia/part3/3p1590.html

http://www.eyewitnesstohistory.com/yellowfever.htm

http://books.google.com/books?id=ERFK1ojA22IC&dq=yellow+fever+in+philadelphia&pg=PP1&ots=VaheKisns3&source=citation&sig=295BNRJ3QTRYcjWV8KRQIfd_dR4&prev=http://www.google.com/search?hl=en&client=firefox-a&channel=s&rls=org.mozilla:en-US:official&q=yellow+fever+in+philadelphia&btnG=Search&sa=X&oi=print&ct=result&cd=2&cad=bottom-3results#PPR12,M1