1. R. Brown, A. Gray, Riemannian manifolds with holonomy group Spin(9), Diff. Geom. in honor of K. Yano, Konikuniya, Tokyo, 1972, pp. 41–59.
2. Ends of metric measure spaces and Sobolev inequality;Buckley;Mathematische Zeitschrift,2005
3. Refined Kato inequalities and conformal weights in Riemannian geometry;Calderbank;J. Funct. Anal.,2000
4. Une suite exacte en L2-cohomologie;Carron;Duke Math. J.,1998
5. G. Carron, L2 harmonic forms on non-compact Riemannian manifolds, Preprint 2007. see arXiv:0704.3194v1.