My pick for the Evidence Live session, is a series of 4, by Doll and Bradford Hill (alphabetical order of authorship):

1950: Smoking and carcinoma of the lung: preliminary report.

1954: The mortality of doctors in relation to their smoking habits: a preliminary report.

1956: Lung cancer and other causes of death in relation to smoking: a second report on the mortality of British doctors.

1959: Lung cancer mortality and the length of cigarette ends: an international comparison.