•Broms e Bennermark
.....(1967)
•Atkinson e Cairncross
....(1973)
•Atkinson e Potts
..............(1977)
•Mühlhaus
.........................(1985)
•Heinz
................................(1988)
•Leca e Dormieux
.............(1990)
•Sozio apud Negro
............(1994)
•