Medical interpreters : where are the books?

Now that the US has a Certified Medical Interpreter exam, the question is, where are the books, the training manuals? Am I missing something? There are more material here in Japan, although not a huge amount yet, on medical interpretation, than in the US. Nothing on Amazon I could detect in the line of "CMI exam made easy". Too early one would comment. If it were here, I assume the launching of the exam would  come with a serious selection of books in too tiny characters, not the US door stoppers hefty volumes. It might come sooner her, to prepare for the US exam, than in the US.