@article{DCG_1992__7_4_131186,
     author = {P. Valtr},
     title = {Convex {Independent} {Sets} and {7-Holes} in {Restricted} {Planar} {Point} {Sets.}},
     journal = {Discrete & computational geometry},
     pages = {135--152},
     publisher = {mathdoc},
     volume = {7},
     number = {4},
     year = {1992},
     zbl = {0748.52005},
     url = {http://geodesic.mathdoc.fr/item/DCG_1992__7_4_131186/}
}