Media type: E-Article Title: On the Existence of Flat Planes in Spaces of Non-Positive Curvature Contributor: Bridson, Martin R. imprint: JSTOR, 1995 Published in: Proceedings of the American Mathematical Society Language: Not determined DOI: 10.2307/2160630 ISSN: 0002-9939 Keywords: Applied Mathematics ; General Mathematics Origination: Footnote: Access State: Open Access