@article{10_4153_S0008439525000177,
     author = {Andruszkiewicz, Ryszard R. and K\c{e}pczyk, Marek},
     title = {On rings which are sums of subrings},
     journal = {Canadian mathematical bulletin},
     pages = {874--882},
     year = {2025},
     volume = {68},
     number = {3},
     doi = {10.4153/S0008439525000177},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/S0008439525000177/}
}