2-Tree probe interval graphs have a large obstruction set.

Natasa Przulj Derek G. Corneil 2-Tree probe interval graphs have a large obstruction set. 216-231 2005 150 Discrete Applied Mathematics 1-3 http://dx.doi.org/10.1016/j.dam.2004.06.015 db/journals/dam/dam150.html#PrzuljC05