%0 Journal Article %A Sunder, V. S. %T N Subspaces %J Canadian journal of mathematics %D 1988 %P 38-54 %V 40 %N 1 %U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1988-002-0/ %R 10.4153/CJM-1988-002-0 %F 10_4153_CJM_1988_002_0