Eastwood, Michael GeorgeBaird, Paul2007-11-132007-11-132004Ninth International Conference on Differential Geometry and its Applications / J. Bureˇs, O. Kowalski, D. Krupka, and J. Slov´ak (eds.), pp. 479–486http://hdl.handle.net/2440/39440enConference paper002007328820071112155006