1. Triple points and surgery of immersed surfaces;Banchoff;Proc. A.M.S.,1974
2. Stable mappings and their singularities;Golubitsky,1973
3. Triangulation of semi-analytic sets;Lojasiewicz;Ann. Scoula Norm. Sup di Pisa,1964
4. Elementary Differential Geometry;O'Neill,1966
5. Lectures on Classical Differential Geometry;Struik,1950