@article {Loubna09,
   author = {Mekouar, Loubna and Iraqi, Youssef and Boutaba, Raouf},
   title = {A contribution-based service differentiation scheme for peer-to-peer systems},
   journal = {Peer-to-Peer Networking and Applications},
   publisher = {Springer New York},
   pages = {146-163},
   volume = {2},
   issue = {2},
   year = {2009}
}