Fan R. K. Chung Zoltán Füredi Ronald L. Graham Paul D. Seymour On induced subgraphs of the cube. 180-187 1988 49 J. Comb. Theory, Ser. A 1 http://dx.doi.org/10.1016/0097-3165(88)90034-9 db/journals/jct/jcta49.html#ChungFGS88