Apostol, Tom Mike. 1988. Calculus, Volume 1: One-Variable Calculus, with an Introduction to Linear Algebra. 2nd ed. New York: Wiley. https://archive.org/details/CalculusTomMApostol.
Mendelson, Elliott. 2008. Number Systems and the Foundations of Analysis. Mineola, N.Y: Dover Publications.
Xie, Yihui. 2021. Bookdown: Authoring Books and Technical Documents with R Markdown. https://bookdown.org/yihui/bookdown/.