@article{MTA_2017_2_2_a4,
     author = {Rolf Walter},
     title = {On a minimax problem for ovals},
     journal = {Minimax theory and its applications},
     year = {2017},
     volume = {2},
     number = {2},
     zbl = {1380.51012},
     url = {http://geodesic.mathdoc.fr/item/MTA_2017_2_2_a4/}
}