@inproceedings{inproceedings9b0e9cf7,
title   = {Free unit groups in group rings and division rings: my collaboration with Don Passman},
author = {Gonçalves, Jairo Zacarias},
year = {2017},
doi = {10.1090/conm/688/13828},
publisher = {AMS},
booktitle   = {Groups, rings, group rings, and Hopf algebras : International Conference in honor of Donald S. Passman's 75th birthday}
}