@article{JCA_2000_7_2_JCA_2000_7_2_a12,
     author = {J. Grzybowski and D. Pallaschke and R. Urbanski},
     title = {Minimal {Pairs} {Representing} {Selections} of {Four} {Linear} {Functions} in {R\protect\textsuperscript{3}}},
     journal = {Journal of convex analysis},
     pages = {445--452},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2000},
     url = {http://geodesic.mathdoc.fr/item/JCA_2000_7_2_JCA_2000_7_2_a12/}
}