1. R. Bryant and P. Griffiths: Reduction of order for constrained variational problems and ∫k22 ds, Am. J. Math. (to appear).
2. Curve shortening makes convex curves circular;Gage;Invert. Math.,1984
3. Exterior Differential Systems and the Calculus of Variations;Griffiths,1982
4. On differentiable functions with isolated critical points;Gromoll;Topology,1969
5. On the total squared curvature of closed curves;Langer;J. Diff. Geo.,1984