@article{PORMA_1973__32_2_115196,
     author = {Smithson, R.E.},
     title = {M-isometries},
     journal = {Portugaliae mathematica},
     pages = {109--113},
     publisher = {mathdoc},
     volume = {32},
     number = {2},
     year = {1973},
     mrnumber = {0321029},
     zbl = {0255.54012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1973__32_2_115196/}
}