Knuutila S, Mäki-Paakkanen J, Kähkönen M, Hokkanen E
Hum Genet. 1978 Feb 23;41(1):89-96. doi: 10.1007/BF00278874.
An increased frequency of chromosomal changes and sister chromatid exchanges was detected in 10 women 7 days after smallpox vaccination.