@article{LetchfordPokuttaSchulz2011, author = {Letchford, A.N. and Pokutta, Sebastian and Schulz, A.S.}, title = {On the membership problem for the 0,1/2-closure}, volume = {39}, journal = {Operations Research Letters}, number = {5}, pages = {301 -- 304}, year = {2011}, language = {en} }