Journal of Geometry and Physics
Journal of Geometry and Physics > 2002 > 42 > 1-2 > 166-194
Journal of Geometry and Physics > 2002 > 43 > 4 > 341-344
Journal of Geometry and Physics > 2002 > 42 > 1-2 > 166-194
Journal of Geometry and Physics > 2002 > 43 > 4 > 341-344