A combinatorial problem in geometry
Compositio Mathematica, Tome 2 (1935), p. 463-470
@article{CM_1935__2__463_0,
     author = {Erd\"os, P\'al and Szekeres, G.},
     title = {A combinatorial problem in geometry},
     journal = {Compositio Mathematica},
     publisher = {Johnson Reprint Corporation},
     volume = {2},
     year = {1935},
     pages = {463-470},
     zbl = {0012.27010},
     language = {en},
     url = {http://www.numdam.org/item/CM_1935__2__463_0}
}
Erdös, P.; Szekeres, G. A combinatorial problem in geometry. Compositio Mathematica, Tome 2 (1935) pp. 463-470. https://www.numdam.org/item/CM_1935__2__463_0/