@inproceedings{BachemGroetschel1981, author = {Achim Bachem and Martin Gr{\"o}tschel}, title = {Characterizations of adjacency of faces of polyhedra}, booktitle = {Mathematical Programming at Oberwolfach}, editor = {Heinz K{\"o}nig and Bernhard Korte and Klaus Ritter}, volume = {14}, pages = {1 -- 22}, year = {1981}, }