%0 Journal Article %A Timo Ketonen %A Kaisa Nyberg %T Twisted sums of nuclear Fréchet spaces %J Annales Fennici Mathematici %D 1982 %P 323-335 %V 7 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1982.0720/ %R 10.5186/aasfm.1982.0720 %G en %F AFM_1982_7_2_a16