I've never heard of a book of a diet specifically designed for strictures...its discussed for Crohn's in general.
In regard to strictures, its best to avoid foods that take a while to break down....fried foods, nuts, certain fruits (pinneapple is a death sentence for me), and sometimes decreasing the intake of breads.
You can sort of figure out what to eat logically, what will be difficult to pass through narrowing?