@incollection{27086,
author = {Bernd Fiedler and Peter B. Gilkey},
title = {{Nilpotent Szabó, Osserman and Ivanov-Petrova pseudo-Riemannian manifolds}},
series = {Contemporary mathematics},
volume = {337},
doi = {10.1090/conm/337},
booktitle = {Recent advances in Riemannian and Lorentzian geometries},
editor = {Krishnan L. Duggal},
publisher = {American Mathematical Society},
address = {Providence, RI},
year = {2003},
pages = {53--63},isbn={0-8218-3379-0},
}