Visually C2 cubic splines

[1]  B. O'neill.  Elementary Differential Geometry , 1966 .

[2]  J. R. Manning.  Continuity Conditions for Spline Curves , 1974, Comput. J..

[3]  Wolfgang Böhm,et al.  On cubics: A survey , 1982, Comput. Graph. Image Process..