Ian P. Gent, Toby Walsh. Easy Problems are Sometimes Hard. Artificial Intelligence, 70(1-2):335-345, 1994.
@article{GentW94, title = {Easy Problems are Sometimes Hard}, author = {Ian P. Gent and Toby Walsh}, year = {1994}, researchr = {https://researchr.org/publication/GentW94}, cites = {0}, citedby = {0}, journal = {Artificial Intelligence}, volume = {70}, number = {1-2}, pages = {335-345}, }