Original source FOR the "orders of magnitude" claim seem to usually point back to Fred Brooks Mythical Man Month (5-10x) or Robert Glass (Facts and Fallacies of Software Engineering) 28x. I don't think either of these multipliers are accurately expressed as "orders of magnitude", regardless of them being supported by evidence.
There is some discussion of the topic in "Making Software: What Really Works, and Why We Believe It."
There is some discussion of the topic in "Making Software: What Really Works, and Why We Believe It."