Jonas Spillmann Markus Becker Matthias Teschner Efficient updates of bounding sphere hierarchies for geometrically deformable models. 101-108 2007 18 J. Visual Communication and Image Representation 2 http://dx.doi.org/10.1016/j.jvcir.2007.01.001 db/journals/jvcir/jvcir18.html#SpillmannBT07