http://tobaccodocuments.org/bat_cdc/24966.html
BINNS RSMITH GWILTONS LV. "Changes in the Respiratory Tract of Rats Exposed to Smoke for 5or 7 Days per Week for 6 Weeks". 31 Aug 1997. Bates: 105432913-105432951.
http://tobaccodocuments.org/bat_cdc/24966.html