"Rubis & Cie, un hussard de la cote" [Rubis et Cie, a hussar of the cosat]. Les Echos n° 16380 (in French). Les Echos. 30 June 1992. Retrieved 6 September 2012.
"Rubis & Cie prend 66 % de Vitogaz" [Rubis et Cie purchased a 66 percent stake in Vitogaz]. Les Echos n° 16700 (in French). Les Echos. 3 August 1994. Retrieved 6 September 2012.