For OED, there is no app or ebook, so your best bet is subscribing to the OED web site:
http://www.oed.com/subscribe/.
For a Periodic Table, check out
http://www.freewarelovers.com/androi...able_1.3.1.apk.
Couple of things you didn't mention are enhanced note tracking (
BI Notes - nice for accumulating typed notes against a given starting topic) and mind mapping (
Thinking Space - useful for sketching out essay structure), both available from the enTourage App Store (you'll need to access these from your eDGe to be able to download and install them.