I'm a math student at the sixth semester and I've had my courses in calculus and complex analysis. I'm able to solve integrals with the usual techniques. However, whenever I am confronted with a difficult integral or with a manipulation of integrals, I usually don't know what to do.
So I'd like to read an advanced book on integrals, on how to solve them, how to manipulate them, how to estimate them. Does anyone have a good suggestion on such a kind of book?
Thanks a lot!