@article{MAN_1970__188_162049,
     author = {J. VRABEC},
     title = {Adjoining a {Unit} to a {Biregular} {Ring.}},
     journal = {Mathematische Annalen},
     pages = {219--226},
     year = {1970},
     volume = {188},
     zbl = {0191.03402},
     url = {http://geodesic.mathdoc.fr/item/MAN_1970__188_162049/}
}