Per Year

 @book {NMis09,
   author       = {Natali, Antonio AND Molesini, Ambra},
   title        = {Costruire sistemi software: dai modelli al codice}, 
   year         = {2009},
   publisher    = {Esculapio},
   series       = {Progetto Leonardo},
   month        = {November},
   address      = {Bologna, Italy},
   isbn         = {9788874883349},
   note         = {second edition}
   
}