I don't remember where I read that, sorry. On the general topic though I can recommend Ray Dalio (a retired guy who founded the largest hedge fund), who has some pretty good free stuff online that isn't too jargon heavy.
For example his video at [1] is a pretty time efficient introduction to country-level debt dynamics (and it's endorsed by some high level people like the Khan Academy guy), and he also has a free book [2] that goes into detail for bunch of historical cases.
