@article{Renda05,
author     = {Renda, M. Elena and Straccia, Umberto},
title      = {A personalized collaborative Digital Library environment: a model and an application}, 
journal    = "Information Processing & Management",  
volume     = {41}, 
number = {1}, 
pages      = {5--21}, 
publisher = {Elsevier}, 
year       = {2005} 
}