@article{PORMA_1994__51_1_47310,
     author = {Echi, Othman},
     title = {Transfer of the notion of -rings to fibre products. {(Transfert} de la notion de -anneaux aux produits fibres.)},
     journal = {Portugaliae mathematica},
     pages = {13--23},
     publisher = {mathdoc},
     volume = {51},
     number = {1},
     year = {1994},
     zbl = {0828.13010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1994__51_1_47310/}
}