Premise: And if you look at any major textbook in international economics--such as the perennial best seller by Krugman and Maurice Obstfeld--you still find that the monetary half of the book is very largely based on the papers Mundell wrote in the early 1960s.

Hypothesis: If you look at any major textbook in international economics, you'll see that it is based on papers Mundell wrote.
Relation: entailment