TY  - JOUR
AU  - N. Hindman
AU  - D. Davenport
TI  - Subprincipal closed ideals in ßN.
JO  - Semigroup forum
PY  - 1987
SP  - 223
EP  - 246
VL  - 36
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1987__36_134898/
ID  - SF_1987__36_134898
ER  -