1. Tinycards
2. Study
3. Coffitivity
4. Evernote
5. Easy Study
7. Sworkit
8. GoConqur
10. Sleep Time
11. Exam Countdown
13. Photo Math
15. EasyBib
If bibliographies aren't your forte, this app will let you scan books and it'll give you the correct referencing in literally every style you can think of.