@article{PORMA_2006__63_4_53547,
     author = {Ferreira, Gilda and Oitavem, Isabel},
     title = {An interpretation of  in {-NIA.}},
     journal = {Portugaliae mathematica},
     pages = {427--450},
     publisher = {mathdoc},
     volume = {63},
     number = {4},
     year = {2006},
     zbl = {1124.03033},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_2006__63_4_53547/}
}