The second volume studies Riemann integral theory and series theory:
The third book studies multiple integrals, curve integrals, surface integrals, Fourier series and Fourier transform.
It is broader and deeper than our advanced mathematics, and the examples are very rich (except differential equations).
Suitable for college students with learning ability. There are 3 volumes of 5 18+66 1+538 1700 pages.
Choose a certain volume to read according to your personal needs.