@article{AscheuerGroetschelAbdelHamid1999, author = {Norbert Ascheuer and Martin Gr{\"o}tschel and Atef Abdel-Aziz Abdel-Hamid}, title = {Order picking in an automatic warehouse}, journal = {Mathematical Methods of Operations Research}, volume = {49}, number = {3}, pages = {501 -- 515}, year = {1999}, }