The number of articles written on personas are emmense. The value of the articles is debatable as most are based on “best practice” on a single case
A couple of books has been published: Alan Cooper started in 1999 with his “The Inmates Are Running The Asylum”, recently “About Face 3.0″ arrived, written together with Robert Reiman and David Cronin. I wrote my dissertaion in 2004 “Engaging Characters and Narrative Scenarios”. In 2006 Adlin and Pruitts Pruitt released: “The Personas Lifecycle”. I 2007 Mulder & Yarrs published “The User is Always Right“.
During the summer of 06 I tried to collect what I could find on the net. The result is an enormous list that I willingly share with others. More has arrived and will be added (when I find the time). You can see the list here in PDF.