Free to read
H. Jerome Keisler
2 free books by H. Jerome Keisler.
- Elementary Calculus: An Approach Using Infinitesimals3rd edition (online, free since 2002) · 2002 · Read at people.math.wisc.edu ↗
- Elementary Calculus: An Infinitesimal Approach2nd/3rd Edition (2012 for Dover print) · 2012 · Read at people.math.wisc.edu ↗