Metric spaces, convexity and nonpositive curvature. 2nd edition. (English) Zbl 1296.53007
IRMA Lectures in Mathematics and Theoretical Physics 6. Zürich: European Mathematical Society (EMS) (ISBN 978-3-03719-132-3/pbk). xi, 309 p. (2014).
Reviewer: I. G. Nikolaev (Urbana)