Clegg, D. A., O'Hara, B. F., Heller, H. C., & Kilduff, T. S. (1995). Nicotine administration differentially affects gene expression in the maternal and fetal circadian clock. Brain Research. Developmental Brain Research, 84(1), 46-54. https://doi.org/10.1016/0165-3806(94)00152-p (Original work published 1995)