“…The obstacle problem for quadratic functionals of the form (1), (5) and under the Dirichlet boundary condition has been studied by Hildebrandt, Widman, Fuchs, Duzaar, Wiegner and other authors (see [4,5,6,7,8,9,10,11,12,13,14] and the references therein). Various obstacles of the type u(Ω) ⊂ K have been treated, where K ⊂ R N .…”