Is there any place ELSE in the HFSJ book where the <resource-ref> tag is discussed other than in question 9 at the end of Chapter 11?
NO
I looked all through Ch11 and other places in the book. If not, then there is no way, by reading the book alone, that the reader could answer the question correctly.
HFSJ uses the 80-20 approach, it tell you the 80 part, and the 20 part, you need to take pain and read ( in fact just SKIM ) the specs. This is what i call as the 'specy' nature of the exam. My advice is, even if you look into the spec areas, which the book points to, its enough. No need to dig and read the complete spec end - end !
Unless anyone objects, I am going to submit a minor errata on this to
Dont do it. I object. Its not a errata. ITs just your frustration that's making you think like that since you didnt see that thing in the text associated with that chapter. hth