I find the information included in this app useful, but different from the info in the EOPR. Which makes me wonder which one in correct. Not sure how you could figure this out. Like for instance, with Elemi, the chemical makeup is completely different between the two. Aside from this, the misspellings drive me batty. It makes the app appear very unprofessional in my opinion. Since I do refer to it often, and the info is still there, albeit misspelled, I gave it 4 stars. But I still feel the EOPR is a more complete guide. So I still lug that around too. (Im a nurse, Ive got to have some real knowledge behind what I say.)