@article{DCG_1986__1_130984,
     author = {E. Welzl},
     title = {More on {k-Sets} of {Finite} {Sets} in the {Plane.}},
     journal = {Discrete & computational geometry},
     pages = {95--100},
     publisher = {mathdoc},
     volume = {1},
     year = {1986},
     zbl = {0598.52007},
     url = {http://geodesic.mathdoc.fr/item/DCG_1986__1_130984/}
}