Preprint number: CP3-Origins-2010-56
Author: Andrew Swann (CP3-Origins)
External link: www.ems-ph.org

Published in Handbook of pseudo-Riemannian Geometry and Supersymmetry, IRMA Lectures in Mathematics and Theoretical Physics, vol. 16 (ed. Vicente Cortés), European Mathematical Society, 2010, pp. 455-474.