Per Sort

@proceedings{esawVII,
   doi = {10.1007/978-3-540-75524-1},
   editor = {Gregory M.P. O'Hare and Ricci, Alessandro and Michael J. O'Grady and Oğuz Dikenelli},
   isbn = {978-3-540-75522-7},
   publisher = {Springer},
   series = {Lecture Notes in Computer Science},
   subseries = {Lecture Notes in Artificial Intelligence},
   subtitle = {7th International Workshop, {ESAW} 2006, Dublin, Ireland, September 6-8, 2006 Revised Selected and Invited Papers},
   title = {Engineering Societies in the Agents World VII},
   url = {http://link.springer.com/10.1007/978-3-540-75524-1},
   volume = 4457,
   year = 2007
}

@proceedings{esawVI,
   doi = {10.1007/11759683},
   editor = {Dikenelli, Oğuz and Gleizes, Marie-Pierre and Ricci, Alessandro},
   isbn = {3-540-34451-9},
   publisher = {Springer},
   series = {Lecture Notes in Computer Science},
   subseries = {Lecture Notes in Artificial Intelligence},
   subtitle = {6th International Workshop, ESAW 2005, Kusadasi, Turkey, October 26--28, 2005, Revised Selected and Invited Papers},
   title = {Engineering Societies in the Agents World VI},
   url = {http://link.springer.com/10.1007/11759683},
   volume = 3963,
   year = 2006
}