@Article{ 
  chemar08,
  author = { Chermisi, Milena and Martellotti, Anna },
  title = { Fixed point theorems  for middle point linear operators in $L^1$ },
  journal = { Fixed Point Theory and Applications },
  year = { 2008 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1549/ },
  note = { cvgmt preprint}
}