Recipes for 15th level Adept 3's?Follow

In the Prima guide, all the 15th level, rare scribe spells (such as Essence Shift Adept 3) are blank as far as where to learn the the recipe. Does anyone know the name of the scroll or book so I at east know what I am hunting down.

Thanks.

The rumormill has told me that these books, "Advanced Scholar 15" (or something along those lines, search the broker for "15") were added after the other low-medium level Advanced Scholar books. I can absolutely assure you however, that these books do now exist. I have a level 27 Sage, and I have every craftable Adept 3 spell in my recipe book (I even have my future books lined up in my bank through level 34). I also currently have an extra one of these books that I am holding on to for my Alchemist alt.