Giaquinta M. Mathematical analysis : an introduction to functions of several variables / M. Giaquinta, G. Modica, 2009 r=on-line. - Текст : электронный.
Giaquinta M. Mathematical analysis : linear and metric structures and continuity / M. Giaquinta, G. Modica, 2007 r=on-line. - Текст : электронный.