Second Fundamental Form for Varifolds and the Existence of Surfaces Minimising Curvature John Hutchinson Indiana University Mathematics Journal 1986 text pdf 10.1512/iumj.1986.35.35003 10.1512/iumj.1986.35.35003 en Indiana Univ. Math. J. 35 (1986) 45 - 71 state-of-the-art mathematics http://iumj.org/access/