@article{MM2_1986__57_155190,
     author = {Michael Wiegner},
     title = {On minima of variational problems with some nonconvex constraints.},
     journal = {Manuscripta mathematica},
     pages = {149--168},
     publisher = {mathdoc},
     volume = {57},
     year = {1986},
     zbl = {0605.49005},
     url = {http://geodesic.mathdoc.fr/item/MM2_1986__57_155190/}
}