I think the "Ace..." book is a good source of
questions but yes, a lot of the answers contain imprecisions and errors, more or less blatant as the case may be.
Maybe usable as source and then finding your answers in the good ole ATPL notes?
Miles Magister, what sort of youngsters? If without ATPL preparation perhaps books such as Flightwise 1&2. HTBJ is pretty "heavy going" (no pun...) if you haven't been at least through some ATPL groundschool.