@article{oai:tsukuba.repo.nii.ac.jp:00015668, author = {Grytczuk, Aleksander and Vorob'ev, Nikolay T.}, issue = {1}, journal = {Tsukuba Journal of Mathematics}, month = {Jun}, pages = {63--67}, title = {On Lockett's conjecture for finite groups}, volume = {18}, year = {1994} }