Robert Dautray, Jacques-Louis Lions ; with the collaboration of Michel Artola, Michel Cessenat and Hélène Lanchon ; translated from the French by Alan Craig ; translation editor, Ian N. Sneddon ; 1, 2. -- Springer-Verlag, 2000. -- (Mathematical analysis and numerical methods for science and technology / Robert Dautray, Jacques-Louis Lions ; v. 5-6).