@article{Rud:71b,
  journal = {Rev. Roumaine Math. Pures Appl.},
  volume = {17},
  title = {On {B}oolean matrix equations},
  author = {Rudeanu, Sergiu},
  year = {1972},
  fjournal = {Acad\'emie de la R\'epublique Populaire Roumaine. Revue Roumaine
              de Math\'ematiques Pures et Appliqu\'ees},
  pages = {1075--1090},
}