1. March of Dimes (2022, January). Preterm Birth. Retrieved December 1, 2023, from https://www.marchofdimes.org/peristats/data?reg=99⊤=3&stop=63&lev=1&slev=1&obj=1
2. March of Dimes (2022, January). Birthweight. Retrieved December 1, 2023, from https://www.marchofdimes.org/peristats/data?reg=99⊤=4&stop=45&lev=1&slev=1&obj=1
3. Martin, J. A., Hamilton, B. E., Osterman, M. J. K., Curtin, S. C., & Mathews, T. J. (2015). Births: Final data for 2013. National Vital Statistics Reports, 64(1), 1–68.
4. Martin, J. A., Hamilton, B. E., Osterman, M. J. K., Driscoll, A. K., & Mathews, T. J. (2017). Births: Final data for 2015. National Vital Statistics Reports, 66(1), 1–70.
5. Osterman, M. J. K., Hamilton, B. E., Martin, J. A., Driscoll, A. K., & Valenzuela, C. P. (2023). Births: Final data for 2021. National Vital Statistics Reports, 72(1), 1–53.