Resources for learning integral calculations

Question

I am willing to learn about integrals . So i wonder is there any systematic book about the topic that goes progressively in difficulty and complexity . My current level is about knowing the basic methods and theorems about the topic .

Answer 1

One of the standards books used on the North American continent is Calculus by Michael Spivak. He does go through integrals progressively. Check the exercises at the end of the chapter regarding integrals.

Answer 2

Boros and Moll, Irresistible Integrals, Cambridge University Press 2004 has some very nice content.