@article{oai:tsukuba.repo.nii.ac.jp:00015920,
 author = {Karpilovsky, G.},
 issue = {2},
 journal = {Tsukuba Journal of Mathematics},
 month = {Dec},
 pages = {403--417},
 title = {The center of crossed products over simple rings},
 volume = {13},
 year = {1989}
}