For those of you that can't tell, I am a huge mobile apps fan! Not only do I access my family trees through my phone, but basically run my life through it. Kroger digital coupons, ordering through Amazon, GPS tags, banking, bookshelves, and my QR code scanner are all on there and I pretty much use them daily. As a working professional, mom, and wife, it is a way of life that has saved me more than once. So any mobile app that I can find that will help me organize my research is worth a try.
Zotero is a website that has quite a few apps to choose from for storing citations and references, including the option to capture images of text for some apps. The apps that are provided are mainly for Android, but there are a few options for iPhone and iPad. Basically you can create a library of references, add tags, sort, and organize everything you upload. It is easiest to sort everything by surname or location, but others may find some other organization scheme helpful. Next you can create notes, books, and other media citations that can be added to continually within a folder. Think of it as a virtual binder. Then you can access your files through the app whenever you need them. I have found sites and apps like Zotero extremely helpful especially when traveling or when another researcher contacts me for citation information.
Check out the different apps available from Zotero here.