Bank of England Quarterly Bulletin: Digital Currencies

PDFs:

"Innovations in payment technologies and the emergence of digital currencies": http://www.bankofengland.co.uk/publications/Documents/quarte...

"The economics of digital currencies": http://www.bankofengland.co.uk/publications/Documents/quarte...

Plus much commentary at FTAlphaville: http://ftalphaville.ft.com/