1.)Rowles, D. (2014). Mobile marketing: how mobile technology is revolutionizing marketing, communications, and advertising. London: Kogan Page.
The first chapter of this book discusses who is using mobile technology. Chapter fifteen is all about QR codes in particular. Lastly, the reference section is divided into chapters. The reference section on QR codes gives helpful links that might be useful.
2.) Murphy, J. (2012). Location-aware services and QR codes for libraries. Chicago: ALA TechSource, an imprint of the American Library Association.
This book is gives ideas and instructions on how to use QR codes in libraries. It gives great information on the variety of uses that mobile technology can have.
3.) Walsh, A. (2011). Blurring the boundaries between our physical and electronic libraries. The Electronic Library, 29(4), 429-437.
This article focuses on academic libraries, but it has some practical applications to public libraries. This article looks at QR codes and RFID tags. On page 433 it discusses how QR codes could be used to make a better library experience for patrons.