Hi, I'm wondering if someone can point me to "rigorous" developments of the path integral formulation. I've mostly seen arguments based on chopping up a line into a discrete set of points and then taking the limit as the number of points goes to infinity and integrating over all possible values of the infinite number of points. I am convinced by these arguments, but I am interested in some of the formalities...particularly some of the intermediate steps. It seems like quite a big jump to the final result, and and I am interested in some of the justifications. Surely this must have been done rigorously at some point....though it doesn't seem that many QFT books describe the details (with good reason). Thanks.