The impact of length and mathematical operators on the usability and security of system-assigned one-time PINs.   [PDF, BibTeX, ]
Patrick Gage Kelley, Saranga Komanduri, Michelle L. Mazurek, Richard Shay, Tim Vidas, Lujo Bauer, Nicolas Christin, and Lorrie Faith Cranor.
In 2013 Workshop on Usable Security (USEC), volume 7862 of Lecture Notes in Computer Science, pages 34–51, April 2013. Springer. © Springer-Verlag  DOI:10.1007/978-3-642-41320-9_3