Ferber K H, Hill W J, Cobb D A
Am Ind Hyg Assoc J. 1976 Jan;37(1):61-8. doi: 10.1080/0002889768507409.
Bladder tumor cases at a dye manufacturing plant showed a statistically significant reduction in incidence of tumors following the advent of process changes and strict industrial hygiene control. A useful method of statistical analysis is employed which may have wider use, especially in cases lacking complete epidemiological data.