Eyal Hameiri Ilan Shimshoni Estimating the Principal Curvatures and the Darboux Frame from Real 3D Range Data. 258-267 2002 conf/3dpvt/2002 3DPVT http://csdl.computer.org/comp/proceedings/3dpvt/2002/1521/00/15210258abs.htm db/conf/3dpvt/3dpvt2002.html#HameiriS02