Luis M. de Campos Jörg Gebhardt Rudolf Kruse Axiomatic Treatment of Possibilistic Independence. 77-88 1995 conf/ecsqaru/1995 ECSQARU db/conf/ecsqaru/ecsqaru1995.html#CamposGK95 http://dx.doi.org/10.1007/3-540-60112-0_10