%0 Journal Article %T GMJ volume 31 issue 3 Cover and Front matter %J Glasgow mathematical journal %D 1989 %P f1-f2 %V 31 %N 3 %U http://geodesic.mathdoc.fr/articles/10.1017/S0017089500007813/ %R 10.1017/S0017089500007813 %F 10_1017_S0017089500007813