@article{PORMA_1970__29_1_115104,
     author = {Fantham, P.H.H.},
     title = {On invariant multiplications in a category},
     journal = {Portugaliae mathematica},
     pages = {13--26},
     publisher = {mathdoc},
     volume = {29},
     number = {1},
     year = {1970},
     mrnumber = {0294434},
     zbl = {0218.18005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1970__29_1_115104/}
}