Media type: E-Article Title: Lecture Notes in Mathematics: The energy Contributor: Cornea, Aurel; Licea, Gabriela Published: Springer Berlin Heidelberg, 1975 Published in: Lecture Notes in Mathematics (1975), Seite 120-134 Language: Not determined DOI: 10.1007/bfb0087305 ISBN: 9783540075318; 9783540380191 ISSN: 0075-8434; 1617-9692 Origination: Footnote: