Gilbert, PJ., Rollmann, B., Rondelet, J., Mercier, M., & Poncelet, F. (1981). Mutagenicity and Alpha-hydroxylation of N-nitrosopyrrolidine and N-nitrosopiperidine - a Possible Correlation. Toxicology, 22(4), 345-352. https://doi.org/10.1016/0300-483X(81)90028-7 (Original work published 1981)